The Loudspeaker-5
18 SOUND
Bass, midrange and horn/compression driver
Copyright 2025 © Troels Gravesen
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DRIVERS CROSSOVER CABINET WORKSHOP PICS MEASUREMENTS
So, what's the point of yet another The Loudspeaker? And
The-Loudspeaker-5? Where is #4? Actually #4 was a version with vintage
JBL 2226H midrange drivers. I have a pair in mint conditions, and
despite quite a few have been for sale on eBay, very few look really
good. Some even having had new outer suspension. Long story short,
very few people would be able to make such a speaker and then what's the
use?
This was some two years ago and part of my reluctance to launch this
TL-5 was space. I really do not have the space to store speakers like
these and my
Ellipticor-28s have become steady in our livingroom. They fit our
livingroom and do what I need. These TL-5s will have to go as well, but
I like making them.
When projects have been in the drawer for too long, things may happen.
Initially I used a pair of JBL 2123H bass drivers for my TL-4, but I
couldn't get my eyes of an 18" 18 SOUND bass driver, the 18LW2420-8. For
obvious reasons I know that an 18" can do stuff, and why not just widen the TL-4 to make room for an 18" bass
driver? Placed in some 150 litres it makes an F3 of around 40 Hz and
with the inevitable room-gain it goes straight to 30 Hz. More than
enough!
Like the TL-3 and -4, this TL-5 will
feature a Hypex FA501 module powering the bass, because it
allows as little as 15 watts for the mid-horn section and it allows equalising
for even deeper bass and endless adaption to room conditions. For those
who can't stand the thought of active bass, there will be a fully
passive version as well. There are people who cannot stand the thought of
a power chord to a speaker. Why, I can't tell.
The TL-5 will be tuned for 95 dB sensitivity. This costs a little
frequency wobble above 16 kHz, but actually the compression driver and
horn does make it up to 26 kHz, enough for most. It has come as quite a
surprise to some TL-1-2 builders that they CANNOT hear the
super-tweeter, which only works above ~9 kHz! Some think it is tuned
extremely low. It is not! It is flat with the horn - people just can't
hear the upper octave due to age - or whatever.
Should you really want some extra zing in the upper octave, add the
Viawave GRT-145-4 and I'll show you the simple crossover needed and
placement of driver. This will increase the level above 15 kHz, and
maybe some like it.
Regarding the 18" bass driver: I have gone through countless 18" driver
data sheets, and there are many. Exceptionally many. I'm sure a lot of
these will be suitable for this project - even with the same software
for the Hypex as provided here, but as always, I can't guarantee the
performance, but my guess is there will be quite a few, but please do
not ask if this or that bass driver will do. I can't tell.
For midrange there was no doubt it has to be the 18 SOUND 10NMBA520. I
love it! Simply a great midrange driver.
And the horn/compression driver with a couple of copper caps will rival any
ribbon, Beryllium, even diamond tweeters you can find. It can make
cymbals sing like they should. I haven't heard
any better treble. Period!
The number of
builders having done the TL-1, TL-2 and TL-3 by far exceeded my
expectations. This is a huge speaker and I really did the TL-1 for myself to first hand experience
what a seriously large speaker would do to my perception of reproduced
sound. It changed it forever. I've heard big speakers at shows, but
never had a pair in my living room.
Having a lot of builders certainly gives ideas and one builder,
Tobias, made an interesting two-piece cabinet. I like it because
it's easier to handle and store. The need for bass cabinet volume comes
from making the cabinet deeper and I have no problem with that. Also the
top can be made more appealing - well, matter of taste, but I like it a
lot.
Again, please go through the tips page. All items, please. If any of these points seems alien to you, please do not engage in the TL-5. This is NOT a beginner's project.
Basics:
3-driver speaker.
Dimensions: 55 x 60 x 117 cm, WxDxH (height without feet). I suggest
30-40 mm feet.
System sensitivity: 96 dB/2.8V/1 meter.
Impedance: 8 Ohms.
Power requirement: 20+ wpc from Hypex version, for all passive, 100+
wpc, the more the better.
Power handling: Enough! Take care of neighbors - and your ears! When
distortion all of a sudden goes really low, we tend to turn up the
volume. Tinnitus is a serious condition.
Useful links (Please
follow all links before e-mailing!):
http://www.troelsgravesen.dk/tips.htm
http://www.troelsgravesen.dk/tips.htm#CONSTRUCTION_OF_CROSSOVERS
http://www.troelsgravesen.dk/crossovers.htm
http://www.troelsgravesen.dk/LCR-RC.htm
http://www.troelsgravesen.dk/Inverted-Polarity.htm
http://www.troelsgravesen.dk/choices.htm
18 SOUND: NSD1095-8 (8 Ohms) compression driver and XT1086 horn.
18 SOUND 10NMBA-520-8
Click image to view large.
18 SOUND 18LW2420-8, 8 Ohms bass driver.
Take care when lifting! 12.4 kgs!
These bass drivers are gigantic!
Download specs here: NSD1095N-8 XT1086 10NMBA520-8 18LW2420-8
Click image to view large
My plan was 27 mm Baltic birch - but hard to find these days, so instead
I found some 26 mm bamboo boards more than suitable for the project. I
bought 4 sheets of 63 x 260 cm and believe me really heavy to get on top
of my car for transport! This bamboo material has relative high density.
The outer layer is around 4-5 mm thick, which leaves plenty of room for
sanding, much better than <1 mm outer veneer of Baltic birch.
Braces and Hypex
compartment from 20 mm Baltic birch.
Braces are approx dimensions. Adjust to your conditions depending on
panel thickness used.
Bass cabinet net volume is around 160 litres minus port/braces/driver/Hypex
comp., maybe 150 litre. Damping materials add some 10-15% virtual
volume, so around 170-175 litre effective volume. This makes F3 = 39 Hz
and with the inevitable room-gain we have a response down to 30 Hz.
Believe me, it goes DEEP! Increasing bass cabinet volume to (18 SOUND)
recommended 220 litre only lowers F3 by 3-4 Hz. Your choice!
With two Ø 100 mm ports of 20 cm length we have a port tuning of 28-29 Hz.
Go to your local home-DIY shop and buy a piece of 100 mm (ID) drainpipe
and cut 4 pcs @ 20 cm. On these shores 107 mm outer diameter.
The midrange/horn Cabinet
Click image to view large.
Maybe trolley wheels would be good!
I used some 3 mm rubber pads between bas and MT cabinets.
This time I used 26 mm bamboo panels. Heavy!
Oak fillets in places.
Making the top front panels.
Routing plan for the horn.
Chamfer the cutout to fit the horn.
Left: Chamfer mid driver cutout to allow free
air ventilation.
Right: Test assembly of bass sections.
Assemble in sections. Make sure all is
right-angled.
Left: The front panel is not glued, but
attached with screws.
And there are holes for neodym magnets to hold the front grill.
Preparing the midrange cabinet.
Left: Add felt to all internal panels. Fasten
with
vinyl glue.
Right: Add acoustilux to all internal panels. Same as felt.
Left: Gluing the ports in place. Use PVC
glue.
First time setup in workshop during crossover
fine-tuning.
As experienced before, this is a totally different ballgame compared to
traditional hifi. The bass, the midrange, the treble... Don't know where
to start. All of it is better. How it renders the recording room, being
a studio, a small jazz club, a large concert hall, etc. It makes you realise,
again, small speakers just cannot do this, no matter how good they are.
And this while still a lot of work on the midrange and bass crossovers
needs to be done. Here we have the bass working a bit higher than before and
the bass-mid crossover is completely different from previous models.
The horn does all the treble, no need for a super tweeter, quite
similar to the TL-3, only tuned some dBs higher. Actually the horn goes
up to around 36000 Hz, albeit a bit ragged above 20 kHz, but who cares.
This is a phenomenal compression driver.
So, lots of hours with the simulation software, lots of hours wiring it
up and lots of hours listening. This is how it goes until you have no
further ideas of improving the sound.
My first-to-hear friend came over and was knocked over: "OK, on my way
home I'm going to visit my brother at the hospital - and I'm going to
ask the nurses to take me in and sedate me heavily, preferably in a
coma, because I'll never
be able to accommodate speakers like these". No point in listening to "hifi"
when this is possible". I think he'll get over it, but the soundstage
here is something than can never be accomplished from a small 2-way - or
even a fairly large classic 3-way. The drivers here alone can be had for
less than 2k€! Think about it!
We had to celebrate the occasion and actually it wasn't Arran, rather a
triple cask Aberlour.
Preparing the frames for front grills. I used 12 mm casting plywood.
In total 16 pcs 8 x 8 mm neo magnets (per speaker) holds the grills in
place.
Look here how to make the front grills.
Front grills helps you listening to the music rather than "the
speakers".
A few comments on
MEASUREMENTS before you start interpreting the readings below.
First of all, if we think measurements will
tell us how a speaker sounds, we're wrong. The perception of sound is
way too subjective to be reflected in any measurements we can perform. A
loudspeaker system is meant to give us a satisfying idea of an acoustic
event and for some people a pair of 5 USD ear-plugs are enough, others
spend 200 kUSD on a truly full-range pair of speakers - and the latter
may not be happier than the former.
Measurements may give us an idea of tonal balance of a system, i.e. too
much or too little energy in certain areas, although dispersion
characteristics play a vital role here. A two-way 7+1 and a three-way
7+4+1 may display similar horizontal dispersion, yet sound very
different. Measurements may tell us about bass extension if far-field
measurements are merged with near-field measurements. In addition to
this, ports may contribute to bass extension. Most of we diy'ers do not
have access to an anechoic room for full-range measurements from
20-20000 Hz.
What cannot be seen is what kind of bass performance we get in a given
room. Bass performance is highly dependent on in-room placement of your
speaker and the same speaker can be boomy in one place and lean in
another. Actual SPL level at 1 meter distance and 2.8V input is useful
for en estimate of system sensitivity and combined with the impedance
profile may give an idea of how powerful an amplifier is needed to drive
the speaker to adequate levels.
What measurements do not tell is the very sound of the speaker unless
displaying serious linear distortion. The level of transparency, the
ability to resolve micro-details, the "speed" of the bass, etc., cannot
be derived from these data. Distortion measurements rarely tell much
unless seriously bad, and most modern drivers display low distortion
within their specified operating range.
Many people put way too much into these graphs and my comments here are
only meant as warning against over-interpretation. There are more to
good sound than what can be extracted from a few graphs. Every graph
needs interpretation in terms of what it means sonically and how it
impacts our choice of mating drivers, cabinet and crossover design.
What measurements certainly do not tell is the sonic signature of the
speaker, because speaker cones made from polypropylene, aluminum,
Kevlar, paper, glass fiber, carbon fiber, magnesium, ceramics or even
diamonds all have their way of adding spices to the stew. Nor do
measurements tell what impact the quality of the crossover components
add to the sound, from state of the art components to the cheapest of
coils and caps, they all measure the same if values are correct, yet
sound very different.
NSD1095N-8/XT1086 horn, SPL without any crossover. This driver does well
above 20 kHz.
Midrange and horn driven from crossover. Point of crossover around 1680
Hz.
To configure a DIY kit and get a
written offer including shipping cost, please use the DIY kit
configurator in the Jantzen Audio website:
https://jantzen-audio.com/diy-kits/
Remember to add terminals when ordering at Jantzen website. No longer included in kit.
All technical questions to troels.gravesen@hotmail.com
Hypex modules
For driving the 18" bass drivers we need power. Lots of it. Thus the Hypex FA501.
Go to Hypex page to download further info.
Actual program for the TL-5 here.
CROSSOVER-LAYOUT
BACK TO INDEX
Check this out before start making crossovers:
http://www.troelsgravesen.dk/tips.htm#CONSTRUCTION_OF_CROSSOVERS
Click image to view large.
I had some copper caps that were longing to be used.
The Jantzen copper caps are smaller but do the same!
I placed two resistors for R2 as in case you want to use an attenuator.
Here mounted in the crossover boot.
Crossover layout, bass, passive version:
For bass we need a really low-DCR coil, hence
a C-coil doing 0.07 Ohm!
My test coil was 0.42 Ohm and does reduce SPL around 1 dB, and we need
low-DCR to keep up with the MT section. With my Parasound A21+ I could
just turn up the volume 1 dB to match the MT section.
Speaker wiring
Pay notice, midrange must be connected with
inverted polarity, plus from crossover goes to minus!