Troels Three Way Classic Bookshelf

Hello,
I've built a few amplifiers from these pages, but this is my first speaker build!
I'm planning on building the Troels Three Way Classic Bookshelf:
Bookshelf-3WC

I work in fabrication, so I had a friend I work with draft it for me. The drawings are too large to attach here, so here is a link to them:
https://1drv.ms/f/s!AoKqL-JHTdcAhJo7LkCvKj_OKBBrLw

(diyaudio says file size cannot exceed 976.6 KB. If anyone can tell me how to post a 1.5MB file let me know, and I'll direct post it here. And if my link ever expires PM me for the files.)

I have a friend with a CNC, so I'm going to take advantage of that too!

I'll use this thread to document my progress. Progress might be slow, but stay tuned!
 
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Your link doesn't work because it requires signing in to something.

Only skimmed the article but the aperiodic loading is interesting and might suit the wall loading. Do you intend to take detailed measurements after construction?

The configuration looks good to me for use in real homes and is similar to the speakers I am supposed to building for the new house when more pressing projects have been addressed. Not sure about the Allison link since the design doesn't follow his approach nor would it need to with a few more books to create a soffit arrangement which would be even better.

Does he say what the felt is for? It looks too flimsy to damp the panels and is an inefficient location for absorbing the lower frequencies because the particle velocity is zero at the wall for the normal modes. Not saying it is insufficient to do the job just curious about the reasoning.

Good luck with build and it will be interesting to see how you get on with the configuration.
 
Hmm, not sure why the link doesn't work. I tested from a random unsigned-in computer and it seems to work. If anyone needs the files, pm me and I'll email them to you. They are very detailed, and any cabinet shop should be able to build from them. The construction is rather simple, but it will save someone from any interpretive work from Troel's website. If anyone wants a flat pack, and is local-ish. I might be able to arrange as well. PM me for that too.

I have two older Rel Strata III subs, so with a mini dsp that I have I plan to make a quasi 4-way, using the subs below where these speakers roll off.

I will take some unscientific measurements in my living space with REW once I get them set up. I'm in the midst of a move, so the measurements will come a little later.

Your link doesn't work because it requires signing in to something.

>>>
Do you intend to take detailed measurements after construction?
<<<
 
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S P L U T T E R ! . . . 15 crossover components ! ?

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WOW ! :eek:

FIFTEEN crossover components in a bookshelf speaker. :nod:


B&W manage with 4 components in their 2-way DM602s ...

... and they sound AWESOME ! :cheerful:


I'd stick to a 2-way & keep all the extra resistors, inductors & capacitors to an absolute MINIMUM. :eek:

Less is more ? :rolleyes:

Nar ... MORE is better ... right ? :confused:


Si. :)

t.S.E.c

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Less Gold Lettered Capacitors & BIGGER Magnets ?

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I think I must be missing the point ? :confused:


Why spend a million bucks on 'needless' ? expensive crossover components ...

... & end up with an 8" driver, which looks as though it has a pretty darn tiny magnet.


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I also don't exactly get WHY one would want to try & merge the performance of these 3 drivers together ? :eek:


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It kinda looks like you end up with a really weird spaghetti junction of overlapping frequencies. :hypno1:


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That ^^ looks CRAZY to my simple minimalist mind ! :eek:

& so the SHARPLY defined 2-Way was invented. :rolleyes:

This tape will self destruct in 5 seconds . . . . .


Si. :)

t.S.E.c

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I don't see what your problem is.

-15 parts in a 3-way is actually quite decent. This is because you have a 3rd driver that requires 2 xover filters in addition to the other 2 with theirs. On the principle of a 2-way with 4 parts, means the 3-way would have about 12 in theory.

-Fewer parts or more parts than average does not mean the sound will be better or worse. Resistors are not bad, and they are inexpensive. "Minimalism with respect to necessity", which means you should have what is required, but as simply as needed to get there.

-Tiny magnets? That is your basis? Some of the best bass was from tiny magnet acoustic suspension designs where the enclosure did the majority of the suspension damping. That is an 8" driver, and I would not call that a tiny magnet. It is enough Bl apparently to do the job, and SS does know what they are doing.

- Why do you pick the drivers you want to use? Because you do. Let's not belittle someone's project because you don't see the merit here. Most drivers' overlaid unfiltered responses will look like that, and the last graphic in post #7 actually looks really good. These are the filtered responses and the sum. I think you self-destructed for no particularly good reason.

- Yes, the xovers do have a bit of bling. Troels sees merit in using more expensive xover parts, as well as being a kit designer for Jantzen-Audio. They supply him the parts, and his builds are at least partially paid for by Jantzen-Audio due to their business relationship. However, 5 resistors in a network does not mean it is a fool's errand. My best floor-standing 2-way has 9 resistors in the network, 5 of which are in the tweeter's circuit, and you wouldn't know it listening to them.

Later,
Wolf
 
Also, let's try to remember diy is about fun and experimentation.
For the last 7-8 years I've had a pair of simple 2-ways. Just a few parts in the crossovers. Although I've enjoyed them immensely, after listening so long I am now fully aware of their limitations, and want to try the near opposite approach. Maybe I'll learn something, and enjoy the process in the meantime! :D
 
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" this is my first speaker build! "


I guess for a first build I wouldn't consider such a complex, specific & expensive thing a learning tool.


" They supply him the parts, and his builds are at least partially paid for by Jantzen-Audio due to their business relationship. "


Good to know.


" SS does know what they are doing."


I have a pair of lovely Scan Speak tweeters which I wouldn't swap for the world ...

... they work very nicely in a 2-way, in conjunction with an 8", but with a generous magnet.


Good luck if you decide to build them & hope it goes well.

How much do all the drivers & crossover parts cost BTW ?

Just curious.


Si.

t.S.E.c

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Thanks for sharing, tech looks solid both in theory and supported measurements, go right ahead you may learn something new hopefully pleasant. Although it does seem to some bent on keeping it simple that the drivers are overlapping and two way may have been good enough however decoupling the mid-range from the room and woofer at around 308Hz and excessively damping the mid-range compartment may give you a solid sound stage. The designer may have his own reasons for also crossing over at 3000Hz using the current slope. Am more draw towards 2000Hz at this time. There are also many techniques of improving the design further but it is solid as it is now
 
" Do people still smoke weed and listen to music anymore? I think they should. Some people need to chilllllll "



I couldn't agree more. ;-)


Making a few personal observations from the information at hand, is a natural thing to do.

If as has been said here, one isn't 'allowed' to discuss a loudspeaker project without having listened to it ...

... you may just as well say, let's DELETE about 95% of what's in the Forum !!!


I suspect that this design 'may' well suffer the fate of 'many' small 3-ways ...

... in what I can only describe as a kinda 'electronicy acousticy veil' ( Stoner Rock term ? ;-) ...

... as all the overly complex filter slopes & acoustic attributes of the drivers & cabinet ...

... merge into an overlapping primordial audio soup.

( I'll no doubt get some comments on THAT one )


I wouldn't even THINK of bringing the X-over down to 2K, that bit's GREAT at 3K ...

... & Scan Speak do know how to put BIG magnets into great sounding tweeters ...

... they just need to BEEF UP the ones on those 8"s from their tweeter magnet size.


There's nothing limiting about a sharp punchy lil 2-way design IF it is done well, 3K X-over essential.


Small 3-ways that I've heard, tend to smear the vital mid-range & give a 'nostalgic' feel to things.

Might be ideal if you want a good 'cosy & warm' midrangey vocal music type box.

'Perhaps' small 3-ways aren't so great for your Stoner Rock or Electronica fan ? ... Mmm.


Those are the 'opinions' ...

... now here are the 'facts'.

I don't listen to much jazz BTW ... But do like the Doobie Brothers now & again. ;-)


Si.

t.S.E.c

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There are very sound reasons for using three, rather than two, drivers, and Troels has explained this many times on his website. The main motivation seems to be to merge the off-axis responses more smoothly between a woofer big enough to produce decent bass, on the one hand, and a tweeter physically small enough not to beam excessively. You also avoid the ragged upper end of most woofers bigger than about 7".

Alex
 
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" ragged upper end of most woofers bigger than about 7" "



Hi Alex.



This is very true, from what I have learned looking at zillions of frequency specs. for woofers & listening.

There are few 8" woofers that can do that.

The Scan Speak 'possibly' can't ... I haven't seen the specs.



The 'Volt' 8s are one of them that easily CAN.

Come with an ENORMOUS 3Kg or so magnet.

Very light cones.

X-over at 3 KHz without a worry in the world.

And a pretty handy super-LOW resonant-frequency thrown in.



Importantly they 'play GREAT' for every genre of music.



I'd put all the dough dropped on tons of fancy & expensive X-over components ...

... into a good basic driver that will never cease to amaze !

I guess I like 'em !



Si.

t.S.E.c

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I've built the Discovery15 Speakers from Troels website and they sound fantastic.
It took me way more time than anticipated to build them as I really underestimated the time needed for the woodwork. They were the first speakers I put together and it was a great learning experience.

Looking forward to your progress updates.
 
The speaker unit used in the bookshelf speaker, is from SS Discovery series...they are not specially expensive,,,but sound ok...i have used some of the bigger bass from this serie

total price for standard component and driver ,,with all you need for the bookshelf ,,
about 700euro....

remember..what sound good for one person..maybe another person think they sound bad...
i have listen to many type of speaker in my long life,,and found out ,that the most important thing, is the room where they play

for me are small 2 ways speaker only for fun

best bjarne