The secret to successful active loudspeaker cabinets: Learning from luthiers!

Unfortunately the video was cut short due to battery running out.
It was fortunate though, as the file size is still enormous, and takes me 2 and a half hours to upload!!!
Arrgh. I'll have to severely limit the length of my future videos for this new format.

[Nihilst]

Hi Janos! Last time I was in the garage, where I expect to manufacture my wooden tonearm due to your proposal, I met one of the leaders. The way he talks is the exact opposite to how you do it. He found that idea really strange, told me multiple reasons why that shall not work well. But then I remembered you. The calm one, and as it is in my nature too I grinned and let him talk. At least I got the chance to make it there. They got a lathe and other tools. It was funny to see such an uneven person. I wish you still had an e mail address shared, so we could exchange more easily how in detail how I fabricate this tonearm.

[dannixon]

Your the best man.
Keep up the fantastic sharing of wisdom.
Your impact on my 30+ year Audio journey CANNOT BE OVERSTATED.

[frankradtke]

Loudspeakers regarded as Musical instruments and not only as an technical object. Really nice.

[earkivaren]

Dear Janos. You indeed opened a can of worms!! Some agree, some disagree, but all the comments, no matter how strong the position is held, are written in a friendly tone, which is so rare nowadays. A big thank you to all commentators! And looking forward to further explorations on this fascinating topic. Claus

[hugobloemers]

This is a very interesting subject, I am looking forward to the next installment.

[erickuehne]

Really interesting subject, thank you! A couple things I didn’t hear you mention: The thicker braces are primarily for structural support as the string tension on the bridge exerts hundreds of pounds of force. The thinner braces, sometimes called tone braces, are just for transmitting vibration across the grain of the wood. Sound travels about 10 times faster along the grain then across it, so tone braces help to compensate for this and even out the resonance patterns.

[EduardBroekman]

Hi Janos, just for clarity, I don't use any bracing for my VOL, there's only one between left and right entirely at the edge which doesn't interfere with the panels - it was just added because the sides where not exactly straight. Otherwise, yes 'bracing' will have such different meanings between speaker builders and instrument makers! Thank you for continuing to expand on this topic.
I hope to fully address the wood quality next time... we have coachwood here that grows locally and which was used for Beale pianos' soundboard, so that's the plan.. although higher quality ply would be another still - I can see how it perhaps better emulates the 'cut' with longitudinal fibres that's used for instruments...
A very different question: did ever consider putting the woofer so it is top firing as well?

[JacekWoczuk]

The main difference is the purpose of bracing. In instruments you want to create resonance, in speaker - as you said - the opposite. Resonance changes original sound, which is avoided in speakers. Resonance creates "colourization" in sound, creates standing waves. The only vibrating thing should be the speaker itself if you want control this

[anandshah]

Have you made on Aperiodic design speakers. I couldn’t get more info on this on the net. Basically I have high qts drivers and wish to use in smaller boxes will this design work

[bartvanransbeeck]

Engineers from kenwood did panel tests, box in concreet, sandfilled, thik massif iron or mdf, sanswich of thin rigid with soft material damped panel resonances the best, like did sand filled sandwich structure....with very thick massif panels the bracing couldn't lift the proper resonance

[bartvanransbeeck]

In the '80ies i built a tannoy autograph with plans of 'la revue de l'audiophyle'...most panels were 12mm multiplex 'bouleau'..top and bottum 18mm...but the horn structure provided the bracing, and it sounded very neutral, the tannoy sounded so airy, music filled effortless all the room, like nomore speaker sound...nomore typical tannoy ...

[iam_mad]

I was considering to reach a bracing across the baffle of the FF125WK cabinet that sticks to the magnet of the driver and at same time could transmit to the side walls, while adding a bit dividing of the inner space for 2 ports above and below.. 🤔Same time I thought seeing the guitar´s port with the star like bracings around, thats a good spot for the driver 😉

[gerihifi]

Hi Janos, but using bracings in active speakers cabinets would drastically change air (speed, pressure, distribution) == changing frequency? So isnt it than hard to measure the right drivers for? Also playing different genres == different instruments would mean you need at some degree DSP to adjust it? Wouldnt be an OpenBaffle the closest to natural reproducing sounds and beeing like in a live concerts, where the room accoustics wil be my 'active cabinet' ? Thanks, Gerald....still learning, i'll never stop 😊

[brucermarino]

Thanks Janos.
1. Do you assume that your panels are vibrating that your panels are vibrating at frequencies consistent with the Western musical scale and, if so, doesn't follow that they will not sound good with other kinds of music?
2. Taking the analogy of musical instruments a step further, does it follow that guitar shaped cabinets would improve the sound of our speakers?
Thanks so much, my friend.

[GentielioGaming]

Is a Dynaudio Heritage Special speaker real wood? The advertisement of these speakers when you watch it suggest it.

[HoomanR]

Janos. From a place of pure intuition(mixed with my engineering brain) and more poetry than science, I have to believe that the active(live) speaker cabinet as you speak of works when you are speaking of a low power amplification and highly sensitive drivers .. the intuition part is that a typical instrument creates noise with minimal power (watts) and little to no heat whereas most audio equipment (even low power class A) between the amp and the speaker, consumes massive amount of power and heat in comparison.. so in order to mimic an instrument, in the truest sense of the word, we must get closer to how nature produces sound...

[PlaybackMansion]

Hahaha I don't even want to touch mdf now

Great stuff!

[loureda]

Hi Janos, hopefully this comment gets through and the you tube algorithm does not delete
me again.MDF sucks and has a very synthetic sound from the epoxy and the consistancy of the sawdust.Real wood gives an aliveness because it is grown over many years and the
wood is very irregular in terms of its grain pattern and possesses a wide resonance pattern
that is lower in amplitude than MDF where the sound can be sucked out and confused.I am
fortuneate that I live in the Pacific North west where there is an abundance of various tone woods like sitka spruce, maple, western red cedar etc. On a budget I would go 1/2 inch Baltic Birch and if you want to go further, experiment with one the aforementioned tone woods. Caution, I do not know which of the above will perform the best so you will have to experiment and it will be very expensive.
Regards Lou
Happy Thanksgiving

[edverbeek]

Plywood speaker cabinets sound better not because they resonate more, but because they DAMP the resonances better and more equally than MDF.

And the few resonances of plywood are well above the areas that you would care about.
THAT is why plywood cabinets sound better.

[AmazonasBiotop]

Thanks! As you know by now I don't agree with that rabbit hole of active cabinets. And I think and listening to you maybe soon for a year when you try to explain the principles of it and it all those explanations just making me more certain that it is a bad idea if you don't like that extra, altered and added sound/presentation. But we are all different. 👍

I understand the microphone capture ALL sounds that you can reproduce from a good LP (if we have that what is stored in the Grove as baseline.)

Then that LP is containing "all" or the most essential of the sound information otherwise we would not enjoy a single recording..

And the active loud speaker cabinet panels are excited by the resonance frequencies for the given loud speaker cabinet panel. When playing that LP.

Each panel (read side of the box) will have each one a different resonance frequency. Depending on type of wood, thickness, mass, size, water content and so on. (That is why they tweak the tone of the guitar by removing some thickness, mass and reduced size of the wood but that were the instrument and not a reproduction device as a speaker are.)

Yes I can get that some can like the added color that has nothing to do with the live event at all as seen below.

It is should be easy to confirm by several different test strategies. One of them is:
Take a recording (LP) play it with those active cabinets and let say it increases by actively vibrating at a frequency and a range of those frequencies that someone so much personally can like.
And of course there will be some frequencies are not effected at all and others that is very excited and is in the panel/s resonance frequency just like the guitar example. So for simplicity if we have the most excitement/vibrations as a example at 555 Hz (if that frequency is there the panels mass, size, humidity and so on is making the panel to vibrate and "sing" at their "most".)
Record with a microphone the lovely altered performance.
Now play (reproduce) back that recording trough the system again!

The same frequencies will be reproduced plus the added +X dB increase that is at 555 Hz from the first playback that is now in your recording..
Again the active speakers will get excited at of course again at 555 Hz with +Y dB! Record that performance with your microphone now you got a recording (+Y dB @555 hz) of a recording that had (+X dB @555 hz)..

As you see you can repeat this procedure if record a reproduced recording, and it will SHOW you now MIGNEFIED (+Y+X+..) which frequencies the active vibrating cabinets are exciting (amplifing).

You do not catch that when you listening as it is not that obvious as in this test procedure we show case it more obvious and magnified. We are usually preconditioned and used to this sound signature when we have listening to our active cabinets for 10 thousand of hours or so.

It is unnecessary to point out that it will be unbearable to listening to after some recording iterations (it is actually "magnifying" the DISTORTION that the active cabinets are actively amplifying and adding). Yes the same issue will happen with "dead"/braced cabinets also but most likely after MANY more iterations because nothing is flat reproduced. And they are not trying to resonance and amplify any frequency area at all by cabinet design.

There is other tests we can do also but my posts are always getting to long anyway.

Yes MDF/HDF may be piss bad but it has desired properties that solid wood has unfortunately not. (It is funny to reflect on that you are so determine to highlight only the negative sides af the material when there is positive properties also. So I feel the need to bring them up.)
If you want to make thousands of speaker pairs then you want a material that is uniform and predictable that don't varying from tree to tree. You want something that is predictable that you can count on in more ways than one.

That guitar (or any instrument for that matter) resonance body has nothing to do with ANY speaker cabinet what so ever.
It is just a nice and appealing idea that is likable and stroking our brain in the wrong direction in my opinion.
If the test above is not enough then think of the resonance body of a viola, violin, guitar, cello, double bass. As we get bigger and bigger instrument the resonance body is amplifying different frequency RANGES. As the size increases the lower it's whole frequency range is pushed down and it loose the ability to produce higher frequencies.
Therefore the need of DIFFERENT sizes of the basically same type of instrument.
Those VOL active cabinets has ONE size and therefore only produce resonances at that specific frequency range for that size and will not help out and have ANY activity at all in the range of a viola or violin and so on.
And the body shape of those instruments is actually making the sound radiating from their resonance bodies at a much more complex pattern than a box shaped "active cabinets".
And how can some speakers as dipole/open baffle somehow in some occasions sound that relatively "good" when their is NO BOX at all to begin with? Maybe just that is a hint that the active cabinets maybe is a rabbit hole.

Thanks, for the explanation video that with my limited knowledge just convince me more that it is a rabbit hole that you want us to follow you down into and play around. 🙏👍🤣🎼💞🎶🎵