Speakers' Corner
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June 2014

New Speakers to come

The last three of months have been busy. Two speakers from ScanSpeak drivers. A capable 3-way from Discovery drivers delivering an awful lot of good sound for a very modest price tag - and the other a very small and rather expensive mini-monitor from new drivers not even ready for release yet.
The ScanSpeak Classic 3-Way has been on the to-do list for a very long time and the Discovery drivers were not even developed at the time as my initial thinking was around the Classic series of 22W/13M/1" dome. However, these affordable drivers deliver quality we didn't dream about some 20 years ago. Better voice coils, more linear response, etc. The level of transparency these Discovery can deliver is quite remarkable and it's all up to low-loss suspensions and rigid cone materials with modest - and ear-friendly - break-up modes.
The ScanSpeak 3-Way Classic will be launched soon.


12WU crossover mounted on rear panel.

Music

Last, but not least, a lot of time has been spent installing a new tonearm on my Lenco L75 turntable and getting to know proper set-up better by doing actual measurements. A protractor has been acquired and the Adjust+ software from Feickert Analogue is currently being tested. An article on why I listen to vinyl rather than digital is in preparation. 

April 2014

lt's been a while since last Speakers' Corner update and a lot of things are in pipeline, but building cabinets take time. For the speaker below I had help from Jesper (Ekta Grande builder) and Jesper made the cabinets seen below and I'm pleased to launch the best SEAS speaker I've ever made. The details can be found here, or click image below.

Also recently launched is a test of  a new SEAS coaxial driver, the C18EN001/M. I'm currently seeking a suitable bass driver for a passive 3-way system, nothing decided yet, so please do not ask.
Having the mid and treble from the same point source is special and I'm looking forward to realising this project.

Janyary 2014

Happy New Year!

ScanSpeak Discovery W18/8434G00-R2604/832000-D2604/830000

Two different front panel layouts and four different crossovers to be tested to make the best of affordable drivers. This is stepped baffles for all. If you have a router - and you need one to make loudspeaker front panels - you can make what's seen above and get the best from simple second order crossovers.

November 2013
Launch of ATS-4 construction.

 

The smallest and the biggest! Above ScanSpeak 5F/8422T01 full range driver. The smallest driver I've ever had. To the right the most ambitious construction ever launched on these pages, the ATS-4, the best from AudioTechnology and ScanSpeak.

The 5F together with 10F/8414G10 have been tested on these pages and will find application in some future projects. The 5F as a mini-mini for laptop used together with a small DAC/AMP unit.

The ATS-4 has been under way for more than half a year. Actually it started last winter when the Jenzen ATS was finished. Not that I wasn't satisfied with the Jenzen ATS, but projects like these take a long time and at the time you're finished you already have the next speaker in mind.
The ATS-4 provides dynamic capability in line with my OBL-11 construction and it's really hard to compete with a 95 dB 15" bass driver on an open baffle. The ATS-4 comes with a significant smaller footprint and the price to pay is some 200 watts for the bass section, something that fortunately comes cheap these days. The other price to pay is three times the cost of the OBL-11, "small" and good = expensive.
The "thing" about the ATS-4 is the use of a dedicated upper-bass driver, a special high-ohmic 8" driver in a closed cabinet. Spoiling the 100-200 Hz range pays off in improved transient response, i.e. dynamic contrast as the buzzword goes these days.

Building the cabinets has taken several months and for once, I don't have ideas for further developments! If it had to be, it would be the same thing, only bigger from 12+10 inch bass drivers and 2 x 6" for midrange - but I do not have room for this, so it won't be. Happy reading.

October 2013

Autumn colours from my bonzai beech trees.
Soon they'll be twenty years old and in another twenty years I think they'll be really nice.

I've had a box of drivers from ScanSpeak, enough for fall and winter projects. Small full range drivers for tiny computer systems, Discovery midbass drivers for small 2-ways of which one will be tuned for bookshelf placement; never done that before. The new 18W/8535-01 will be used in a larger 3-way with two 8" Classic bass drivers (winter project).
Before all this I need to finish the new 4-way from AudioTechnology drivers and the new ScanSpeak 7140 Be dome. This project has taken longer than anticipated due to elaborate cabinet work and client projects, but it will still be finished before the end of the year (read below 08-08-2013). Mid cabs are finished and only thing left are the tweeter panels - and fine-tuning of the crossover.

I'm pleased to see more reports back on Jenzen projects: http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm#builders-response. Shows that people are still not afraid of building large speakers despite extensive cabinet work and high cost.
 

08-08-2013

Pleased to announce the Ellam FLEX 3W - although launched 1½ month ago - but it's summertime and weather has been unuasually kind to us this season and speaker work has had low priority.
Part of my holidays were spent extending my workshop removing some 4-5 tonnes of concreate and clay from the basement! No speaker work for more than a month! Actually needed a break after the Ellam FLEX construction. Given the 2-way, 3-way and 4 tweeter options available this took more time than anticipated.

Next in line is a 4-way, kind-of, an extension of the Jenzen ATS. The idea here is to add an 8" in between the 10C77 bass and the 18H middriver. Targets are higher sensitivity, more weight to the bottom end and better transient attack by adding a dedicated driver to the 100-200 Hz range.
Rather than the usual 8" and 10" in parallel in the same enclosure I have chosen to use the 8" in an closed 16 liter cabinet - and preliminary test strongly suggests enhanced speed and transient attack in the vital area.


Test bass cabs with Jenzen-ATS top and new crossovers.


Cabinet design will be the same as -ATS, only 5 cm taller - and in Baltic birch. Expected launch before the end of the year.


By the way: If my website looks a bit strange in your current Explorer 10, choose compatability mode as my website apparently is not fully compatable with the latest version of MF Explorer. If you use Google browser there should be no problem, but my pages look better from Explorer compared to Google - for some reason. Damn MS changing things all the time - and not always for the better.

30-05-2013

Two updates here in May:

- Implementation of SEAS T35C002 dome in TQWT, DTQWT and DTQWT-12 constructions. My first full-hearted recommendation for an alternative voicing of the TQWT/DTQWT constructions. A modified crossover and the T35C002 dome provides a lower point of crossover between the JA8008 driver and tweeter. The result is better dispersion in upper-mid/lower treble delivering more presence and a bit more detail. I'm not calling this an -mk3 version as this would mean the end of mk2. Setting up the DTQWT mkII and mkII-T35 aside, I'm sure opinions will be divided to which one is the best. Some may prefer the standard mkII version being a bit more laid back compared to the T35 version where the T35 voicing may be a bit more critical on source material but also deliver more detail.
The DTQWT tweak page is updated with a brief summary and here you can read the full T35C002 story.


- The new Ellam FLEX mini 2-way has been under way for quite some time. Voicing four different tweeters takes time but here we go with the first part of this construction. The Ellam 9800 will disappear and so will the W1500/97 and W1501/95 speakers. I also meant to delete the Ellam XT construction but I'm still getting some response to this construction and despite not as good as the Ellam FLEX offers an easier front panel layout and a good starter kit for first-time diy'ers.
The Ellam FLEX will grow to Ellam FLEX 3W in the near future, so that your Ellam FLEX at a later stage can be up-graded to a true 3-way speaker offering substantial increased sound stage and versatility. The Ellam FLEX can stay as-is and you can use a 24 dB LR electronic crossover at 400 Hz with the 22W Revelator bass driver, either 8 ohm or 4 ohm version. For the passive version the 4 ohms version must be used and we can manage a system sensitivity at 88 dB compared to 85 dB for the electronic version regardless of bass driver used.
The Ellam FLEX 3W passive version will be a mini Jenzen with a substantial smaller footprint but obviously for smaller rooms compared to the large Jenzens.

13-04-2013

Sold out! Making room for new projects was easier than expected although I had to make 3 x 300 litre crates for the Jenzen Illuminators! They went to Schwitzerland.
So, the new project is flexible and called Ellam FLEX, building on the ScanSpeak W15/8530-K00 driver, the best 5" I know of. First there will be a two-way mini from 15W and the 6600 tweeter. Later to be supplemented with the 6620 tweeter and also lower-cost version with the D-R-2604/833000 tweeters, thus 4 options.
Later this will be developed into a 3-way with the 22W Revelator bass driver, either 4 or 8 ohms versions. The 4 ohms bass driver will have a passive crossover but the Ellam FLEX can also be used with an electronic crossover with both 4 and 8 ohms bass drivers depending on your preference. The passive version will allow a system sensitivity of around 88 dB where the electronic option will have to settle with the Ellam FLEX two-way's system sensitivity of around 84 dB.
Fully finished we will have a Jenzen mini, only 25 cm wide. High-WAF? This is in the eye of the beholder, but certainly the Ellam 3W will take up considerably less space compared to the Jenzen range of speakers.

The bass driver can be fitted into the transmission line shown above - or you can make a smaller (less deep) bass reflex design to your preference. Expected launch before the summer holidays. Please do not ask for details before launch.

  
  By the way: It's spring and time for setting up more nest boxes, here for the titmouse, port tuning = 32 mm.
(port = Ĝ32 x 12 mm, volume = 2.5 litre, Fb = 152 Hz) YES, the port can be on the front, the most common question I have.

23-02-2013

"Reviewing" your own speakers is fun - and a bit frightening too. The Illumina 66 had new front panels and had been dismantled for a few months. The Jenzen Illuminators have been out of house for a couple of months and the OBL-11s have been dismantled too as I needed the drivers for other purposes and I hadn't heard them for more than a year. In the meantime my Jungson amp has undergone some major upgrade and how would the speakers respond to better front end gear?


Click images to go to construction website.

The reason for bringing up these three speakers is that they're up for sale. I'm in desperate need for space having five large-scale speaker in our house and some speakers just must go.
So,  with the modded Jungson they all performed a bit better than I'd heard them before. Most surprising was the Jenzen Illuminator delivering a level of transparency on par with the Jenzen D and ATS, which are the speakers currently competing for default living room speakers. Now, having these speakers around I dare say that we can have some of the best sound possible from such different cone materials as long-fiber paper pulp, ceramics, mineral-filled polyprop and sandwich paper pulp! I feel lucky having had the opportunity to compare these speaker drivers in similar sized constructions.

If I had another and larger living room, the OBL-11s could be my one-and-only speakers as they can do things none of the other speakers including Jenzen D and ATS can do. They're easy to drive, they have the low-end dynamic only a 15" on an open baffle can manage - and they can play vocals louder than any other speaker I've ever made.

The Illumina 66 is the little brother here. That said, the best "6+1" I've ever made. These sandwich paper cones have more dynamic headroom compared to any other ScanSpeak driver I've tried.

Illumina 66: Give it 50-100 watts from the best solid state or valve PP you can afford.
Jenzen Illuminator: Give it minimum 100 watts from the best solid state you can afford.
OBL-11: Hmm... This speaker will run with almost anything, from 25 watt PP valve amps to 100+ solid state amps as it has a high-pass filter to the midrange.

Should you be interested in buying these speakers, mail for price and do not expect anything below building cost. And please be within reasonable pick-up distance! No packing and no shipping, sorry. Mail at: troels.gravesen@hotmail.com - and please state where you live.

24-12-2012
What is Your Room Like?

Any sound system set-up should start with this question: What is your room like? Many people set up seriously expensive systems in less than adequate acoustic environments and never render the full potential of their investment.
Almost every day I have to direct respondents to this page: CHOICES. I cannot - and shall not - give any recommendations on what speakers to build, but I can tell people not to build the Jenzen Illuminator if they have 5 SET watts at hand - and not to build the TQWT if they use a 400 watts solid state amps. Generally people are afraid of using large speakers in small rooms - and yes, it can go wrong depending on actual speaker and room placement. 12 sqm is not a whole lot - actually the size of my workshop - and I don't have problems running my Jenzen speakers in my workshop where they can be placed away from the corners. But don't stick two Jenzen speakers in the corners of 10-12 sqm unless you have a digital equaliser. Not recommended.
A speaker may be so tall the response from the drivers may not gel properly at short distance, but a large speaker may be much better energising a 12 sqm room compared to a small 6+1 speaker. That is: The speaker drivers don't have to do much, we have reduced cone movement, we have low distortion and we have more dynamic headroom.
One thing is matching room, speakers and amplifiers, another thing is what can be done to better room acoustics. Sometimes a modest investment in room treatment may be worth more than a new megadollar amplifier - or loudspeakers. Lots of literature is available on room acoustics - and what can be done about it. I won't make a list, but simply point to a few youtube movies on treating your room for better sound:
http://www.youtube.com/watch?v=lbLVjHfHahg. I love this couple - and the wife's body language saying : "Do I really have to in on this?" Very sound advise.
http://www.youtube.com/watch?v=eVZTKIrR6lI. Part one.
http://www.youtube.com/watch?v=qECsSHJXvNA Part two. Sound advise too.
http://www.youtube.com/watch?v=4paIPqORvdc Don't know the language, but have subtitles.
http://www.youtube.com/watch?feature=endscreen&NR=1&v=JQLDIrS8deU. This guy must have had 6 double expresso coffees in a row. I love his AU accent. Have fun!

There are many more movies on acoustics on youtube and take a look around and get ideas.

Next speaker

Next speaker is a Jenzen 3-way made from Audio Tecnology drivers for bass (10C77) and mid (18H52) and ScanSpeak Be dome. Design is inspired by Wilson Audio Alexia. I love this design and despite having the same potential as the other Jenzen speakers, appears quite smaller due to the pyramid mid/tweeter arrangement. Cabinet work is the most extensive yet undertaken, so it will be a month or two before launch. 


Jenzen ATS cabs ready for final sanding before spray paint.

Thanks for all response during 2012 and best wishes for 2013!

25-09-2012
I should go to more hifi shows but every time I do I decide it can wait a while before I go again. The recent show in Copenhagen must be the worst organised hifi show ever with very few exhibitors and few guests too. Maybe I should go to Munich next time. Best sound of show came from Dynaudio and Rockport.


From left Dynaudio, Rockport, Ayon and JBL.

What I missed the most was music. Exhibitors love to play "sounds", like recordings of some fancy drums or a Fender bass played with a plectrum. Simple stuff that will always impress by dynamics. Anyway...
These Dynaudio skyscrapers  for sure did well and had a seamless integration of both bass-mid and mid-tweeter. Well done indeed. 
The Rockports featured new carbon-sandwich cones and I was truly impressed, not least by the mid-tweeter integration. Very well done indeed. Having a small 5" on front mating a side and low mounted 10" bass driver had its shortcomings making the lower mid/upper bass slightly weak but overall a very well executed speaker. The EAR front-end for sure must be mentioned too, these EAR861 bridged stereo power amps (60 watts) made a perfect match to the Rockports. With the EAR868 pre-amp and turntable/12" Jelko this system just played music. Only problem is price. I think a system like this will set you back more than 50 kUSD.
Having played around with 4" compression drivers and huge mid-horns last winter I was keen to hear what JBL and Ayon had made from this approach to reproduced music. The Ayon/McIntosh/Ayon system for sure outperformed the Accuphase/JBL system. Dynamics were truly impressive and leaves direct radiators far behind. Fortunately the guy handling these systems played real music and what became apparent from both systems was the inability to place vocals properly in the soundstage. The transition from the 12-15 inch bass drivers to the midhorn is a key element in making these systems work, and frankly, I don't think it will ever work really well. Direct radiators can - to my ears - make a more credible presentation of vocals and should I try out compression drivers I would go for a 4-way system with an efficient 8-10" direct radiating middriver handling the 200-800 Hz range, a compression driver from 800-6000 Hz + supertweeter. I've heard JBL systems based on this approach and I was impressed although I admit it was many years ago.


The very best sound on show: Stax electrostatic headphones. Here my friend enjoying aural nirvana.

 

 

If little music was played at the show, the records shops gave you the opportunity to bring home some. Buying your high school records can be tempting, and I did. I have these recordings on CD but they leave me cold, thus four freshly pressed vinyl records. Could the magic of high school parties be restored without the booze and the girls? Not quite, but there were surprises. I never heard these vinyls on a good hifi system. Back then it was Beogram 1000/Beomaster radios and some B&O speakers. And the amp had tone controls, even a loudness button to correct room conditions. How would they sound on a modern hifi system? Bob Dylan was disappointing. Nothing but midrange except for the track Desolation Row. This track sounds good and well, you never really finish with the lyrics of this song. The re-mastered AFTERMATH is excellent and brings me back to a time where my record collection was less than a handful. The Doors are true high school music and I wasn't disappointed. Still worth a listen and I'd forgotten how good musicians they were.

26-08-2012
The Jenzen D has been up-graded with a new front panel and a few mods to the tweeter crossover and I'm pleased having this speaker in stock again although space is becoming a serious issue.
Fortunately the Jenzen Illuminator is currently at the ScanSpeak production plant demo-room in Videbaek, and I was certainly curious to hear how they would perform in a room this size and with proper acoustic treatment.

The speakers are driven by a Gamut system, CD-player, preamp and two 200 wpc mono-blocks. These mono-blocks, delivering 400 watts in 4 ohms,  could certainly get the Jenzens swinging like I hadn't heard at home from my Jungson power-amps, in particular the bass response was deeper and more powerful. The room itself made me seriously wonder what can be done to our living-room at home without making it look completely like a "stereo studio". It's bad enough with either the Jenzen Ds or DTQWTs filling the corners. Discrete acoustic panels here and there might further improve acoustics.

What's next? I seriously don't know. I have plans for some ten speakers I'd like to build, but I have to choose, so for the time being I'm cleaning the workshop while waiting for inspiration.

06-07-2012

HiFi Porn

My job in an international company recently brought me to Münich via Frankfurt. In both airports I had plenty of time visiting the magnificent magazine stores we can find in German airports. The amount of hifi magazines we can find is truly amazing compared to e.g. Heathrow or San Fransisco, where you'll be lucky to find more than HiFiChoice and similar - if anything at all. In Germany we can even find two magazines devoted to diy loudspeakers alone. Quite amazing. Germany appears to be do-it-yourself paradise.
What struck me was the increasing number of magazines, almost books, devoted to product reviews illustrated with gorgeous high-res images of drivers, crossovers, cabinets, amplifiers, turntables, etc. In Germany we can even find a high-gloss magazine solely devoted to vinyl playback!
These magazines apparently run on a tight budget despite luxurious print and paper quality as there are no measurements whatsoever. Exquisite photo coverage and so-and-so reviews, mostly praising products far beyond reason. I'm sure manufacturers cover all costs getting the products to the reviewer and back again. The days where magazines would pick what they considered interesting and sometimes launch a bad review seems long gone, maybe Stereophile as an exception, where I recall manufacturers being furious over less than stellar praise of their products.
Appearance is everything and Image HiFi, HiFi+, etc., are magazines that specialise in high-res images and low-cost reviews. The www.6moons.com is the web based equivalent to these printed magazines. 
Basically it's high-fi porn - and I admit I sometimes surrender to the glitter and buy one of them. Manufacturers and reviewers live of one another and bad reviews mean no more products to that reviewer, and as consumers we have to learn to read between the lines even more. This can be quite funny as a reviewer's dissatisfaction with a given project proves quite a challenge in writing positively, and whenever gear has to be mated with specific cables, 200 hours burn-in, etc., we can be quite sure this is a fuzzy product and may call for very specific taste in musical reproduction. Generally reviewers' ability to write very much about very little is impressive. Here's a recent example of a speaker review found on the web:

The stealth reflex port is X's patented solution for a para-aperiodic vent. Its behavioral properties allow for deeper more extended bass from the same or smaller enclosure. In addition it has all the advantages of conventional ports but completely eliminates chuffing. Here X uses an insulating material to reduce the transmission of vibrations. Thanks to this solution the sound requires less resonant assistance from the cabinet which translates into lower displacement through the port. Because its tube is lined with a fibrous porous material, the low frequencies cover a larger spectrum previously possible only by either increasing the size of the overall loudspeaker or the vented chamber.
The imposing stand too is more than plain pedestal. It could be defined as symbiotic extension of the NN. It reflects fundamental elements of X's L.V.T. low-vibration transmission concept or mechanical floor decoupling via a perfectly weight-matched elastomeric suspension. This is said to substantially reduce spurious vibrations into the listening environment and inhibit the production of sound-damaging acoustic feedback. Anima Legata, another anti-resonant technology derived from prior X models, is made up of two surfaces fitted orthogonally into a concentric compressed traction bar within the stand. The volume and variable thickness of the bar eliminates resonance within the stand cavity via more thermo-kinetic dissipation.

 

The best ~30 litre 2-way floorstander

- I've made so far, Illumina-66.htm. The "six-plus-one" is hugely popular for good reasons. Two drivers, a fairly simple crossover, simple cabinet work and usually high-WAF due to small footprint. The latter really depends on overall fit'n finish.

Nothing prevents us from making the best of midrange and treble from a two-way floor-stander and it can even be made to produce some decent bass. For most people hifi is not about recreating a live event in their living room, rather having decent gear giving us an illusion of a live event. Read more from the link above.

What's next

After finishing the Illumina 66 is have started making the final cabs for my Jenzen D speakers. The Jenzen TL cabs found their final destination with the ScanSpeak Illuminator drivers and I need these Jenzen Ds for reference. Quite a few mid-cab front panels were made to possibly improve visual and acoustic properties and the sketch below is close to what they will look like. So far, no changes to the crossover are needed. The front panels are made from 2 x 16 mm laminated black MDF, which I've found to be as dense as HDF. I measured 840 kg/cubic metre, some 25-35% more than ordinary MDF. MDF from the local home diy market is sometimes of quite bad quality.
The cabs should be finished by the end of August and what's next is to be seen. At least 4 speakers are on the drawing board and two of these are low-cost 2- and 3-way designs. 

 

And finally I found a Lenco L75 turntable in close to mint condition. I'm very much looking forward to restoring this spinner with a new plinth and 12" Jelko tonearm. Based on overall construction and principle (idler wheel) this turntable should work as well as my Garrard 401.

The best speaker I've built -

Some people question my statement that the DTQWT is the best speaker I've ever made because I've made quite a few speakers since then and how can I still hold this opinion despite Jenzen D, etc.? Well, the DTQWTs can do things none of the other speakers can do in terms of overall dynamics due to efficiency, mid-tweeter integration and because they don't have a crossover in the critical midrange. These are the three main features. The DTQWTs can play a piano, an oboe, a flute and a saxophone louder than any of the other speakers partly due to the large midrange driver, 8", and the large wave-guided 34 mm dome tweeter. Size matters and regardless of the quality of a 5-6" midrange driver there are limits to how loud they can play. The Jenzens all have less dynamic head-room due to these limitations although satisfactory for most applications (average living room size). The DTQWTs can be played to satisfatory levels with my 45 watts SET amps, something none of the other speakers can do and my 6C33 valves sounds better than my solid state amps. And some mistakenly think the DTQWT are only suited for low-wattage valve amps because they were developed for this, but any good amp can be used with the DTQWTs, they may just not sound as good as they could if you had a good triode amp. There are reasons people bother nurturing valve amps as some require regular service, but we don't get it all for nothing. So, the DTQWTs are still my best speakers regardless of cost and specific areas where some of the others may excel. All speakers are compromises and fortunately the amount of speaker designs seems unendless and there should be one for your taste too.

09-06-2012
The Jenzen Illuminator has been launched and I'm pleased with the result. The 26W bass driver goes deeper than any of the other Jenzens; the price to pay is reduced efficiency and the Illuminator needs a sturdy power amplifier to bring out the best. I've had regrets that the 6640 Be dome wasn't used but this tweeter just didn't perform well in this set-up due to a "reach-out, here I am" quality I wasn't able to handle in the crossover. As always, driver matching has to be tried before any given combination is certain. The 6600 tweeter was doing exactly what I wanted it to do, playing treble - and nothing more. The 6640 will be tried in other speakers to come.
Next in line is a 30 liter two-way from ScanSpeak 18WU/4741T00 and - again - the D3004/660000 tweeter + D3004/662000 as an alternative. Crossover simulation suggests several interesting options and I looking forward to this most interesting part of the project.
28-03-2012
Springtime temperatures should call for garden work and preparing for this year's vegetable garden - and so it does, but speaker work is continuing as I have exiting ScanSpeak constructions in pipeline. Up-coming is a Jenzen Illuminator and the preliminary work is finished; that is, getting the acoustic offset of mid and tweeter right and testing if my preferred crossover topology will work - and it does. In fact, the 18WU driver has an excellent frequency response on the Jenzen baffle making crossover work easy - and simple.

The tweeter will be the beryllium dome and I'm keen to learn how good it is in comparison with my current diamond tweeter/Accuton set-up. My Jenzen Diamonds will be disassembled as I need the basic Jenzen cabs for the Illuminator speaker and the diamonds will have their reincarnation in new cabs later this year. I need these for reference as the deliver the best mid-tweeter level of transparency I've yet experienced and numerous visitors have confirmed this.
After the Jenzen Illuminator there will be smaller two- and three-way floor-standers from the 18WU drivers and I will also use the 4 ohms version of the 18WU drivers to increase system sensitivity, maybe not for low-wattage valve-lovers, but speakers in this category will never be my first recommendation for less than 50 wpc amps.
An adaptor for mating the ScanSpeak 7100 tweeter with my TW034 waveguide have been tried in my DTQWT speakers, offering enhanced resolution and transparency but maybe not the overall coherent sound from the 8008/TW034. Making waveguides is on and off and never really ends as new ideas emerge from time to time in order to improve performance.
So, lots of projects in pipeline, only building cabs takes time.

This winter's live performances included Ravel's Piano Concerto in G-major at the local Symphony Hall featuring an American pianist, Simone Dinnerstein, and it kept us all spell-bound for the entire length of the concert. Look out for this lady, she's something. The first movement in this piano concert really holds elements of Rhapsody in Blue by Gershwin, and I guess Ravel did listen to contemporary jazz music after moving to the US - and I wouldn't be surprised if Keith Jarrett digs into some Ravel piano recordings from time to time.
15-04-2012: In response to my comments above, Piotr/Poland provided this article by Robert Rogers, Oxford Journals, on Jazz Influence on French Music, (4MB) Thanks to Piotr!    

02-02-2012
January and February for sure are diy speaker months! The cold winter months call people to the workshops cutting sheets for cabs, reading diy websites and making all sorts of plans. Well, it also tells most diy business is taking place on the Northern hemisphere - as least based on website statistics and mails received.
What I have noticed over the last 2-3 months is that I get more and more mails I can't answer properly. Questions about strange speakers I've never even heard of or how I think a given speaker will interact with a given room. The latter is really impossible to answer. Whether you buy a pair of speakers or build them yourself you always run the risk of total failure due to poor room acoustics. Too much bass or too little bass are the typical problems and I'm mostly short of suggestions as the only information I have is basic room dimensions. 
Quests for building finished speakers are another frequent topic and having a full-time job this is out of the question. I can hardly cope with my own plans and have ideas for years to come. Sorry!  
ScanSpeak tweeters have kept me busy and I have launched some measurements and an article on a waveguide for ScanSpeak D2904/710003 tweeter. This waveguided tweeter was tested in the DTQWT construction and for the first time found suitable as an alternative for Audax TW034. Better? Hmm... different and in the end a matter of taste - and definitely more expensive.
Out of curiosity I also bought a line stage kit from diyhifisupply and I can fully recommend this product, which can be had for down to 300 USD + two good coupling caps. Not a bad entry into the valve world and it should be trouble-free for years and years. This line stage together with an e.g. JungSon Duro class A amp is an unbeatable combination in terms of cost/performance and can be realised for close to 1000 USD. Today we can have high-performance gear at price that was unthinkable only a decade ago.
Last but not least someone lend me a pair of ScanSpeak 18WU/8741T00 drivers and what was planned as a quick review of one of the Illuminator series, turned into weeks of crossover tweaking. Eventually a pair of stand-mount monitors was the result. Being used to DTQWT and Jenzen speakers it took some time to get used to a small "6+1" again. 150 square centimeters of pulp really can't move a lot of air, thus numerous crossovers were made before I was satisfied - and it gave ideas for future experiments. The Illuminator drivers are not as smooth compared to the Revelator drivers and extra care is needed in crossover design, but these sandwich membranes deliver details former drivers may have been short of. Value for money? Doesn't make sense. You're buying a specialty product with specific design features and you have to pay. And never judge a product based on measurements alone. It may takes many constructions and endless crossovers to get to know a product's full potential.

Check out this interview of Neil Young talking about the inadaquacy of MP3 files and low-fi! Do you know what kind of media Steve Jobs listened to when at home? Thanks to Max/Norway for sending the link!

05-12-2011

November seems a busy month on speaker building. The number of mails have been overwhelming. Hope some of you got sensible and helpful responses. I know some of you didn't because of what is described here: crossovers and this choices but that's how it is. I can't tell if drivers I don't know from own experience will make a good system and most of you writing appear not having measuring equipment to get the crossover right and even the best drivers can be a waste of money without a good crossover design. 

Launching the Jenzen Accu wasn't easy. This is a seriously expensive speaker and I can't help wondering if someone building the Accu will think it's worth the money. So, I had to ask myself if it feels right for me and after several weeks' audition and drivers breaking in I felt it was right. I've missed it every time I had something else running and it makes me confident it's worth while. 
With a speaker like this you have to get past "new-speaker" honeymoon to know if it is right. I always seriously doubt "break-in" as most break-in is taking place in out brains, but I think the Accutons need some break-in. A little rough and edgy at first but smooth and homogenous after many hours of playing. The AudioTechnology bass driver is everything I'd hoped for in the TL cabinet. Articulate and dynamic, even at low levels.
I recently visited a guy having a pair of small stand-mount ScanSpeak 18W/8531-G00 + D2904/700005 speakers in nice black piano lacquer finish (Gamut). He paid more for these speaker than the total cost of the Jenzen-Accu. Now, the Jenzen Accu does take several times the space, but comparatively the Jenzen kit is a steal for the money if you can handle the woodwork.
With the Jenzen Accu I will also start a practice of writing something about the limitations of my speaker constructions, which may discourage a few builders, but limitation is part of every speaker design. I have done this before on very small speakers. Based on response I can see that people often overestimate the soundstage a given speaker can produce. Some people think a small and inefficient speaker just needs a huge amp to get it going - and it may certainly help on some parametres, but it doesn't change the fact that a given speaker is limited by the amount of air it can move as a result of the total membrane area. A midrange driver really shouldn't move much, in fact cone movement should hardly be visible even when played loud. Same thing for bass drivers. Visitors are always surprised seeing - and feeling - the cones of the two 10" bass drivers in the DTQWT when played really loud. They barely move +/- 1 mm - and they shouldn't. 
I would really have liked to launch the Jenzen Accu with the final front panels but the Jenzen cabs will see more drivers before they'll end up as the final Jenzen Accu, because the Accu is likely to be the final statement of the Jenzen series. This is kind of a problem because the incitement to make more Jenzens is diminished by these drivers. How can I make something better, because we always want to make something better? Well, the AudioTechnology version may throw a few surprises too. I hope to have a 18H52 built for midrange with a suitable impedance not needing any attenuation at all. The Accuton C173-6-191E didn't and it pays off.
There won't be more speakers launched this year and I think the Accu is a nice finale to a fruitful 2011 in trying out stepped baffles and simplified crossover topologies improving overall performance.

Last but not least: I've already had a number of mails asking if a 20-30 watt PP/SET valve amp can drive the Jenzens speakers. To my mind they can't. On average we're some 6 dB below e.g. DTQWT sensitivity and we need at least 4 times the amount of power comparatively. The 80 watt Jungson does really well and generally I recommend 100 wpc, being valve or solid state for the Jenzens. Maybe a really good 60-70 watt PP valve amp will do well too, but I don't have such a thing and can't guarantee.
I also want to stress the importance of quality of the amp, in particular for the Accu version. Only a few days ago I had a visitor bringing in an Advantage S150 solid state amp from Bladelius. Now, this is a nice and powerfull amp, easy on the ear and with a wide soundstage but it seriously missed the holographic, reach-out midrange magic. The Accus can reveal much more than this amp is capable of doing and the JungSon outperformed it over and over again - despite costing a fraction of the price. (I only use the power amp section of the Jungson amp).    

01-11-2011
Loudspeakers we don't come across every day! One with limited dynamic capability and one with almost unlimited dynamic capability.

I've had the opportunity to review the Manger MSW transducers and my expectations were high. I had hoped these one-of-a-kind drivers had the answer to phase distortion and impulse correctness, but I was seriously disapointed. These drivers have a high magnitude of nonlinear distortion and fortunately I found another article confirming this, because after decades of praise I was a bit nervous to rock the boat. I don't say these drivers are useless, but they have serious limitations on terms of portraying the depth of an acoustic scenario (lack of dispersion) and they don't go loud before distortion becomes clearly audible.

---o-0-o---

Who would think that a few kilometers from where I live there would be a JBL Paragon loudspeaker fully functioning? The owner bought these back in 1975 and has only had new surrounds added to the legendary LE15 bass drivers. A friend of mine set up the arrangement and we had an enjoyable hour in front the Paragon.
These speakers - or more correctly this speaker - is no less one-of-a-kind compared to the Mangers. I think the 4" 375 midrange compression driver is the most powerful ever produced and mated with the 075 ring radiator and 15" bass driver, this speaker is - if anything - a clear demonstration of what converting  electrical energy into acoustic energy can mean. 

For those unfamiliar with the Paragon design, the above sketch tells what's going on. The most unusual thing about this speaker is the midrange horns pointing towards a huge curved front panel meant to disperse sound into the room; this quite opposite to the tweeters located inside the bass horns and pointing forward. Now, sitting in front of the speaker - on the floor - because vertical dispersion from the tweeters is limited, the usual quest for soundstage depth, spatial information and three-dimensionality is far off. Forget it! This speaker makes music in a room and it does it like few. Time alignment, phase coherence? Forget it! The shocking thing is that when energy transfer is optimised way beyond what we are used to, we may get away with grossly neglecting all the other parametres. This doesn't mean the Paragon is the way to go, because it isn't, but we can go home and seriously think about ways to improve dynamic headroom and reduce distortion. The inability to perform appropriate energy transfer from our rediculously small direct radiating 5-6" middrivers is pinned to the wall.

14 Oct 2011
Jenzen SEAS ER and Jenzen NEXT constructions launched. Pics of the finished cabs have been added. If you have the time and skills in woodworking, you may be in for a treat from modest priced drivers (SEAS ER). The NEXT version doesn't come cheap, but delivers the goodies.
Response has been overwhelming and three ER kits were sold before the paper was dry, so there seems to be quite an interest in large speakers and I feel confident going on with the work developing further Jenzen variants.

26 Aug 2011

It's with great satisfaction I now lauch the Yamaha NS1000M Up-grade Kit. This completes the range of up-grade kits covering the most noticeable speakers of the Sixties, Seventies and Eighties, the Tannoy MG15, the JBL L100 Century and now the Yamaha NS1000M. All three speakers were made in considerable numbers and many are still in service today. 

 

This kit will not be particularly cheap as making good things better takes serious means. The kit is a "closed kit" like the JBL L100 kit, meaning no crossover component values is given here, it comes with the kit. 
I feel confident NS1000 afficionados will find the investment worth while. Substituting the old electrolytic caps makes most of the improvement - and most of the cost. Smoothing tweeter roll-off and re-designing the bass low-pass section provides an overall LR4 topology, which was targeted in the orginal crossover, but not fully accomplished. Adjusting attenuation resistors will allow the same tonal balance as before, only with enhanced transparency and ease of listening.
The beryllium middome is what really makes this speaker, and it's so good it deserves the best. The NS1000 is a special speaker, not to everyones taste, but for those you have the front gear that can deliver the level of resolution these speakers can help come through.

The first Jenzen speakers, Jenzen SEAS ER is close to being finished and I only need to paint front panels to make them ready for presentation, hopefully by the end of September. As I have SEAS CA18RNX drivers on the shelf - and they fit the routings - it would be silly not also to include this version in case someone should have these drivers available. Only the mid crossover needs minor tweaking to fit this driver.
Following the Jensen SEAS ER and Jenzen SEAS CA, the Jenzen NEXT is next in line. All the nextel units fit current driver routings and I can borrow the bass drivers (W26NX002) to supplement the W18NX001 and T25C003.

Since last update I've had requests for speakers below 200 €/pair to 4000-6500 €/pair! Not much in between. Sorry to say that none of these requests can be fulfilled. I have two kits below 200 €/pair (I think), here and here. SEAS and Peerless 5+1 inch speakers. If cabs are made from MDF and not too expensive capacitors are used, I think these can be made from around 100 €/speaker. Most speakers I build are based on curiosity. If I don't have a feeling I can learn something new, motivation is low. Now, 6500 € is another story. First of all, developing speakers this size is a serious investment in terms of time and money. Secondly - and based on history -   nobody builds it, not even the person who asked. Thirdly, I can't get rid of it again - unless I sell it for nothing. Last, but not least, I have the speakers I need, the DTQWT and If I had the space, the DTQWT-12. Regarding seriously expensive speakers, some diy'ers think it's a matter of making "some" cabs and throwing in expensive driver - and then I have to make it all work. It doesn't come that easy. Often a range of cabs have to made to get it right and sometimes the tweeter - despite its price and praise - just doesn't blend well with the middriver and another one has to be found. Cloning the Wilson Audio MAXX3 or Marten Coltrane 2 is not an easy task and in both cases OEM (Original Equipment Manufacturer) drivers are used, and finding substitutes may be impossible.
If you're not suffering economic depression or have lost it all on Wall Strett, two of the Jenzen speakers to come will set you back serious money by using Audio Technology and Accuton drivers - if I can make it work. Buying expensive drivers is gambling, sometimes it works, sometimes it doesn't. These speakers will not be 6000 €/pair, maybe half and the reason I can make it happen is "re-cycling" and borrowing. The Accutons I had to buy though. Not cheap.


28 June 2011

After the 8008-CENTER speaker, the Jenzen speakers are next and I recently cut sheets to get started on the cabinet work as can be seen to the left. "Jenzen" because they are based on the Jensen 1071 project, thus the name Jenzen to make a distinction.
The Jenzen-2011 projects may develop into quite a range of speakers starting with two constructions based on SEAS drivers. As announced previously, SBAcoustics, ScanSpeak, Peerless and Audio Technology drivers may find their way into these cabs too.

DIY is about making quality without paying fortunes and what we can do commercial manufacturers cannot, is totally spoil the drivers with good cabinets. We can spend endless hours making cabs and we don't have to charge anybody, and we can even afford decent components for the crossover. Something that is a serious limitation to a commercial speaker, where working hours and components' cost have to be kept low. 
We can make rock-solid cabs for almost nothing because the cost of MDF is low and even exotic Baltic birch as seen to the left is moderately priced. I paid some 300 USD for all the good 23 mm BB seen on the photo.

Both cabs features transmission line loading and the midcab some 46 mm thick side walls to keep cabinet colouration low. First driver set-up will be SEAS CA26RFX/ER18RNX/T25C003 as seen above. This reed/paper pulp cone midrange is something! Smooth response and resolution on par with even magnesium.

5 June 2011
So, when are we building loudspeakers? If visits to my website hold any relevance to the number of speaker projects initiated, then February is the month where we go to the workshop cutting MDF/plywood sheets. According to Jantzen Audio, this was also the month where most DTQWT kits were sold ever. 


Website visits relative to max.

I admit I have to pull myself together really hard to get started cutting sheets, but once started I get caught up in the process and even think of the next project during the process. Making cabs takes peace and concentration to get it right and every single time I have finished a pair of cabinets, I know how I will make the next pair to perfection. However, the new pair is always another speaker with different cabs and takes new measures to get it right.
Right now a cab (yes, one cab) is made for an 8008 center speaker featuring a small 4" middriver and the Audax TW034 for treble. This time the Audax is used without the waveguide. The quest for a center speaker to supplement the DTQWT is becoming more and more frequent and despite good weather the table saw was taken to the back yard. Hopefully the speaker will be finished before the end of July. The crossover looks easy on simulation and if reality follows prediction, this will be a serious powerful center speaker.

Month of May was mostly spent making client crossovers for a 2-way Audio Technology speaker and two 3-ways based on SEAS and ScanSpeak speakers. The ScanSpeak speaker had its SS 15M exchanged for a SBAcoustics 6" driver and although not as smooth as the SS 15M driver, the sonic results were good. At around 100 USD each these SBA drivers deliver excellent sound, but the break-up nodes in the 4-11 kHz range takes special precaution. A single notch filter can make most of it, but ideally two are needed to make a smooth roll-off. It also has some "rubber" (?) problem around 1.5 kHz, which is not apparent from driver specs. The SB17 is a small 6" driver featuring only 120 cm^2 membrane area, where a SEAS 6" mostly makes 126 cm^2 and a ScanSpeak 6" revelator makes 150 cm^2, thus also claimed a 6½ inch driver. True 7" drivers are rare, but Audio Technology 6I52 is an example with some 165 cm^2 radiating area.


SBAcoustics SB17RNXC35.

The other SEAS project featured twin M15CH002 mids on a wide curved baffle. The SEAS 10" nextel bass driver and Crescendo tweeter completed the set-up. Now, this speaker can obviously be compared to the Cyclop and the main lessons to be learned are these: Use minimum 130-150 cm^2 membrane area for the midrange if crossed at ~250-300 Hz - and if we want a "big" speaker that can play loud. A wide curved baffle allows the middrivers to work all the way down to its point of crossover without any baffle step loss. I render this important and have become more and more concerned with baffle step loss and baffle edge diffraction as -mostly - necessary evils. When we can avoid it, there's a premium. Last but not least both speakers had an all-pass filter to the tweeter allowing true LR2 topology. Stepped baffles may had prevented this, but this was not within design parametres and the benefits outweighed the added complexity.   

02-April-2011
Thanks for your concern! Yes, I'm still alive, only not publishing a whole lot of speakers every second month - mostly due to building amplifiers. That doesn't mean there aren't speaker plans in the drawer, actually many, many plans, but I do have a full time job and cutting sheets takes hours and I needed a break after the OBL-11 as mentioned in the Feb notes.
I have been selling a lot of stock drivers - and buying new ones, enough drivers for at least 6 new speakers. One that for sure will emerge some day is an Ekta mkII featuring HIQUPHON OW4 tweeters, stepped and sloped baffles, simplified crossover and solid cabs. The prototype sounds very promising and hopefully I'll pull myself together for the woodwork before too long - although springtime is ahead and usually calls for alternative occupation.
Next I'm gathering drivers for a range of Jensen-type speakers. Yes, big 3-ways with 10" bass drivers in transmission line cabs and 6-7" mids, stepped baffles and low-order filters. SEAS, ScanSpeak, Peerless (Nomex164 for mid), Ciare, SBAcoustics and Audio Technology drivers are on the shelf for these constructions, some very affordable, some seriously expensive. Please do not ask when these constructions will emerge.
Based on the last two year's experiences, building new speakers have become more time consuming due to new design criteria, and a lot of prototype work follows each construction. The all too common rectangular box is in many ways a bottleneck in making good sound from even seriously expensive drivers, where ensuring proper radiation area and proper time-alignment can make good sound from even low-cost drivers. What doesn't come cheap are good crossover components and I have a lot of reports back from people spending many hours on woodwork and drivers, but fail to spend more than average on crossovers. Even low-cost drivers benefit from proper components. It's like buying a Porsche with a 1.2 litre engine.  
05-Feb 2011
After finishing the OBL-11 things have been quiet speaker wise. Time to listen to music, attend concerts, reading magazines. I read e.g. Stereophile due to the thorough measurements on speakers done by John Atkinson. There are a lot to be learned from these reports and it's interesting to see how e.g. Wilson Audio speakers develop over time, in particular the Watt/Puppy, now Sasha WP, and the Sophia. From time to time I've had the urge to copy the cabinet design, but making a Sasha cabinet clone is extremely time-consuming and something that only a very few will follow. I'm sure the Jensen speaker will make up to any of these two speakers - and the cabinet is much, much easier. I'm pleased to see more respondents to this construction.
What has happened to the WP/Sasha, is a goodbye to the sub/sat set-up, where the mid/tweeter in principle is a full-range speaker supplemented by a subwoofer. The Sasha is a more common 3-way speaker with a point of crossover around 200 Hz. I'm not sure the Watt/Puppy really had a high-pass filter to the ScanSpeak 8545 derivative, but the new middriver, which, by the way, looks like an SBAcoustics driver, certainly has, and displays a smooth, almost 1st order decline, where the woofer more looks like 2nd order. This has worked for me in the Jensen, the PRELUDE and OBL-11. If we use a smaller midrange like the AudioTechnology 15H52 (PRELUDE) we need to raise the point of crossover an octave to around 350-450 Hz to enable the midrange to cope with required power handling. Most good 6" drivers, dependent on front panel dimensions, will do fine down to 150-250 Hz.
The "problem" of having a highpass filter at 150-250 Hz is the amount of microfarads needed for the high-pass filter. The quality of these caps is extremely important and 100 uF is serious money using super caps. 200 uF in total easily mounts to around 5-700 USD or more. For midrange I've experienced good results from
Obbligato Gold caps, and also the Obbligato Film Oil Caps do well for midrange, but not for tweeter; here we need better, and usually super caps are within reach as often only 3.3-6.8 uF is needed.

I've recently had the opportunity of auditioning - and measuring - the Eggleston Andra speaker and this was indeed interesting, not least being able to see if all the nice claims at producer's website really hold water, which they mostly don't. All drivers are standard off-the-shelf drivers (very good drivers has to be said) and the double Morel mids, which turned out to be Morel SCW 636 bass driver, and Dynaudio Esotar makes a seamless integrated soundstage, utterly transparent and dynamic. The point of crossover between mid and tweeter appear to be around 1.5 kHz. The two 12" Dynaudio bass drivers in isobaric configuration truly are outdated and the overall system would benefit from some modern bass driver with a higher mechanical Q compared to these relics. I have to admit I came from a 15"/open baffle bass set-up and found the Eggleston bass lacking punch and speed comparatively.
Now, an Eggleston Andra is serious money, 24 kUSD/pair, and for this we get spotless mids and treble, rock-solid cabs with an impeccable finish, and - electrolytic caps for midrange! I'd say, the most important part of the frequency range, and then electrolytics, albeit by-passed by a Solen cap, but nevertheless. Owner had replaced the entire crossover with really good components and it had paid off. I wonder what caps we will find in the Sasha and Sophia...
Eggleston claims 6.3 ohms minimum impedance; I measure 2.6 ohms! I guess they had a typo writing the numbers :-). They claim -3dB @ 18Hz; this is way too optimistic, -3dB @ 40 Hz seems more like it, not least considering the overall system sensitivity of ~88 dB/2.8V. Here we agree. The lesson to be learned is that DIY can easily compete with even the most expensive high-end stuff when i comes to loudspeakers - if you put all the working hours into it.

Tweaking my Audio Mirror amps for new 6C33 tubes has been truly rewarding, although not completely finished yet. Minor hum remains, but I feel sure I'll find out why some day. These 6C33 really are something. In the current set-up they deliver transparency that made me stay up all night going through my record collection - one of these rare occations that doesn't happen too often. With their 40+ WPC they can make my OBL-11 rock and kick butt like a solid state.

My JungSon amp has been modified to a power amp alone (bottom of page). The JA88D line stage is easily detached and the power amp input wires connected to the two XLR input sockets. The gain of the power amp section makes a perfect fit to my 6N6P line stage and adding a balanced output to the 6N6P is next on my to-do list.