They are very similar, interesting reading your thread. So difficult deciding on what drivers to use. Still have a niggling feeling I should have gone with 18WU Midwoofers instead of the the 22W. Anyway will see how it goes...
It's not that you can flatten it, its that you don't have to. I made the same mistake in thinking when I first started looking at it. You have to deal with (or at least keep an eye on) the impedance spikes on a passive crossover because its part of the circuit, it changes how the caps and inductors are going to actually react. It's a physical electron thing.
Since active crossovers work on the digital signal, not on the physical circuit, you don't have to flatten them. You just don't care. It doesn't affect the crossover. You're dealing with the actual bits of the sound, not the bits of electrons sent to the speaker.
Does that make sense? I'm a CS, so the digital side I get, not sure how to explain the passive side as well.
PS. On topic of the speaker build, looking good! I wanted to make a tower with similar form factor to what you're doing, sent the pics of your Zaph build to my girlfriend as an example and she approved, so you've got spousal factor and I'm sure it sounds good to boot.
The size of these next ones are a lot bigger. Still waiting to see what my wife says when she sees the final size. She does really like the ZRT though. I will put some more details on the ZRT online sometime soon if you are interested. A lot more work in making the curved sides but IMO it does make them look a lot better, and they seem smaller than the same volume in a rectangle.
I'd love more info. For her the size isn't so much the issue (somehow), but the shape and finish is. I won't tell her I'm looking at 4 to 8 liter enclosures....
You're comment on appearance is valid though, curves make things seem smaller. So maybe I should go for that 8 liter monster...
Which do you think is more of a pain, the translam, or pending the mdf? I've read other places not to use mdf but rather hardboard, and from a trip to my home depot it does seem fairly flexible.
The ZRT was a single enclosure so bending the Mdf was probably easier. Certainly less waste/cheaper. The new set require a lot more complexity internally which is where the sandwich method is great. It is going to pose a few challenges in finishing I think as there a lot of joins to conceal.
Could use hardboard perhaps. I found mdf to work well. I used steel pipes as rollers and tie downs to hold while glueing. It did take a long time as I glued 2 sheets of 3mm to one side of each speaker per night. I think I did 8 layers so 4 nights per side x 2 sides = 8 nights in a row with glue everywhere. It ended up pretty smooth though. I used 2 part epoxy to fill in any imperfections.
I have just added construction photos here
Curved Zaph Audio Based ZRT 2.5 - Google Photos. Take a look at the ones with all the straps/tie downs to see how I blended the mdf
I hadn't, they look very interesting, upgrading the miniDSP is probably going to be the next step, look like a very good option
What's the curve for? Aesthetics?
EDIT: The last one looked great by the way, I'm certainly not knocking your aesthetic decisions!
The only acoustic reason I can think of for including the curve is that you may have simulated the pattern of the lobes you'll get, and seen that the pattern will be improved by the banana shape.
Given that you plan to use a DSP, you could probably simplify your build by removing the curve / tilt (unless it is there for aesthetics). Some builds use tilted / stepped / odd baffles for time alignment, but you can handle that digitally.
e.g. I've seen old Dunlavy speakers with stepped baffles, but he began designing them with flat baffles (with rounded edges) about 25 years ago:
Atkinson: Whereas you achieve the time-alignment physically with the SC-VI and the smaller conventional Dunlavy designs by recessing the shallower drive-units, the Magnus has a flat baffle.
Dunlavy: You can use digital components to achieve extremely accurate time-alignment of the drivers. In the Magnus, we are able to time-align the drivers to an accuracy better than 1.9µs, which is an exceedingly small distance, less than a sixteenth of an inch. And we can maintain that over a very, very wide frequency range.
Dunlavy: You can use digital components to achieve extremely accurate time-alignment of the drivers. In the Magnus, we are able to time-align the drivers to an accuracy better than 1.9µs, which is an exceedingly small distance, less than a sixteenth of an inch. And we can maintain that over a very, very wide frequency range.
Loudspeaker designer John Dunlavy: By the Numbers... Page 5 | Stereophile.com
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They are a great set of articles by John. Very sadly missed. I often wonder where his designs would be today given where technology and DSP are at now.
The Ultimate Preamp is a fantastic product. I have tried many different crossover orders and points but the 6db 1st order to me, still sounds far better, gives a better sound stage and a much flatter uncorrected response. But thats just me and everyone has their own opinion as to what sounds better to them. Thats the beauty of the active crossover. You can change things on the fly and have an immediate result and make your decision. And the difference with a fully active system has to be heard to be believed compared to a passive system.
Keep going down the path you are on Mike.
The Ultimate Preamp is a fantastic product. I have tried many different crossover orders and points but the 6db 1st order to me, still sounds far better, gives a better sound stage and a much flatter uncorrected response. But thats just me and everyone has their own opinion as to what sounds better to them. Thats the beauty of the active crossover. You can change things on the fly and have an immediate result and make your decision. And the difference with a fully active system has to be heard to be believed compared to a passive system.
Keep going down the path you are on Mike.
Yes, I thought it breaks it up a bit, otherwise it is a very large singular box. I have designed it so that from my seat each 12MU is exactly the same distance from my ear. I like the look of the Focals which have a similar shape (e.g. the Grand Utopia) so based on that concept.
The engineers at pbn Montana Speakers and Rockport Speakers have advanced the Dunlavy philosophy and tech.
-improved construction materials
-reduced cabinet diffraction
-improved polar response from shorter C-to-C distances
-physical and crossover changes to improve time alignment and phase
-room equalization for bass
-lower distortion
-higher max + transient SPL
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I suggest going for something with more digital outputs than a 4x10HD. I compared the DAC on the 4x10HD to a cheapo $70 DAC I found on ebay, and I actually preferred the ebay DAC. 4x10HD is regarded more for testing what sound you want before settling on something more advanced or analouge. Since my setup has so many drivers I will try to find an active analouge crossover. A passive line level crossover is too comlicated at fourth order and a a passive speaker level crossover muffles the sound too much, especially for the midwoofer and mid diver which would require huge inductors and capacitors. I opted temporarily for a mix with passive speaker level for the Mid driver and the Tweeter, and the minidsp as a line level crossover between the Sub, Midwoofer, and Mid+Tweeter, using only three amps instead of four. The components in the passive speaker level crossover for the Mid driver and Tweeter are small enough not to interfer with the sound quality too much.
Why 10 outputs is more than enough for a 4 way?
I am a bit worried about that. I am currently using a NAD M51 and the cheap DAC's in the miniDSP wont be in the same league
Assume this is to save on 2 extra channels on the amp?
Minidsp 4x10HD only has one digital output and if you use it with a different DAC than inside the Minidsp device it may not match up so good.
Yes, th speaker level crossover between the mid driver and the tweeter is to save an amp and one crappy digital crossover point, at 2000Hz. For the mid woofer I would need very large components to cross it at 70-440Hz that didn't sound good. Also, I had difficulties getting the speaker level crossover to cross where I wanted it to cross, and I could hear a big difference to the minidsp.
Yes, the DACs are not fantastic, but good enough for testing. Been testing for 5 years now.
Yes, th speaker level crossover between the mid driver and the tweeter is to save an amp and one crappy digital crossover point, at 2000Hz. For the mid woofer I would need very large components to cross it at 70-440Hz that didn't sound good. Also, I had difficulties getting the speaker level crossover to cross where I wanted it to cross, and I could hear a big difference to the minidsp.
Yes, the DACs are not fantastic, but good enough for testing. Been testing for 5 years now.
If it was perfect first time we would get bored and have to find another hobbyBeen testing for 5 years now.
Over this weekend I (almost) finished a side-side counter-force woofer cabinet with front-rear ports using two AES TD15S woofers, and was amazed at how little vibration remained.
If you dream about building a BIG Duntech WMTMW topology speaker, give some consideration toward two 12" side-side counter-force woofers instead of one front facing 15. Baffle simulations continue to support using deep shaped edge bevels like the pbn Montana.
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