Any interest in an ASR community speaker project?

[dwkdnvr]

Well, the backside has some little nubs to align the tweeter properly, so 3d printing is probably more practical. I'll send some stl files tonight.

What sort of cnc do you have?

Didn't see this earlier - I just have a generic 6040 machine at the moment. I'm actively evaluating an upgrade path since the work area is really too small for good speaker work - you can do it, but workholding becomes a real problem. I'm constantly having to figure out how to not run into clamps. In theory I have almost all the parts to build a big unit (3'x4' work area), but I'm having to evaluate whether I'm up for the work - it's competing with a lot of other stuff at the moment. Buying a new unit would be $2k+ though (although I could sell my current unit to recoup some of that), which is tough to face when I've already spent the $$$ on upgrade parts.

Got the STL. I got a successful tiny sample print from my printer over the weekend, so I think I'll give printing the waveguide a shot. I haven't really had to work with supports much in the past, so it'll take a bit of experimentation to see whether I feel comfortable trying to print mouth-up. I suspect mouth-down is likely to be easier, but then you probably end up with supports in the flare requiring more clean-up work.

My very preliminary measurements of my CNC'd waveguide for the DA25Tx went pretty much as expected - not awful up to 10k but then fell apart. So, that will be an ongoing design process, and seeing how much work some folks have put into getting it 'just right', one that ultimately might get shelved. I like what the DA25Tx brings to the table, but if a waveguide is needed for that project it's highly unlikely that I'll come up with anything close to what augerpro achieved with the SB26ADC/CDC.

 

[GelbeMusik]

I am not completely opposed to an active design, but I think it makes less sense for this kind of project. Off the shelf plate amps worth using are very expensive and generally big, and using outboard amplifiers and DSP introduces a ton of variability. It might be suitable if a very high end target is preferred.

For me it makes no sense to omit contemporary possibilities. My recommendation is, to aggressively bring these to use. And if it was only for the final integration into the room and/or with subs.

A digital EQ is obligatory. As is a measurement microphone. You'll better cut the wood with the toothbrush than to try DIY without these devices. The implementation of digital EQ can be left to the individual: computer / miniDSP / plate amp whatever.

The design could, and from my perspective should, for several reasons work with a passive XO. Only that the focus is directivity and dstortion, and hence linearity is left for the said EQ. Why not accept a +6dB somewhere if it is easily corrected? Baffle step, who cares?

All what comes next is already lost in personal preferences, right I've seen somebody asking for a 200$ woofer … to be combined with 15$ tweets, which are easily but severely upgraded by some other at 23$.

Good narrow dispersion design ( no affiliation ):

https://heissmann-acoustics.de/en/disco-m/

 

[Lbstyling]

So you would recommend the waveguide surface be printed facing down rather than up?

It depends on the printer used, and the scaffold needed, as this is a trade off against at the advantage of resin filling the part. When resin filled, it's As tough as cast, even tougher with 20% fibre reinforcement.

If painting, I would go visible face down, but if this is a part to be sold, and the machine used is good enough, print around a waxed mold that is the shape of the scaffold you need. That's what the pros do to get high quality parts. You need to know how to program the tool path for this though.

 

[Lbstyling]

Ha, I literally just posted this question to Augerpro's thread on diyaudio. The construction of his waveguides with the alignment nubs being the only points of contact if printed mouth-up seems problematic - either you need significant support structure to help, or you're asking your printer to print an unsupported horizontal surface. I'm guessing that's just asking for trouble.

That really comes down to how well you run the printer. If you keep it in a temp and moisture controlled room with the machine set up for the conditions it's printed in, you would be fine. It's all in the prep.

You could also print it in 2 parts. The faceplate (face up) with only 6mm depth that has mounting nubs that line up to the throat part. Both parts can now be printed solid without using much material.
This also solves fitting a driver to the WG, as the throat can be screwed to the driver before attaching to the WG faceplate. This in turn would allow you to fit the faceplate to the speaker permanently and paint over it if you so wish, reducing diffraction points.

 

[GelbeMusik]

... If painting, I would go visible face down, but ... though.

I didn't realize how far this got already. Did You ever mention to address the vertical suck outs from interference? If we take spinorama serious, these are part of the early reflections, hence their absence would contribute to pleasure. If DIY doesn't go further than the industry standard of ignorance, what shall it?

Alas, I'm just working on a pseudo coax. You're too early.

What are You aiming for?

 

[617]

Didn't see this earlier - I just have a generic 6040 machine at the moment. I'm actively evaluating an upgrade path since the work area is really too small for good speaker work - you can do it, but workholding becomes a real problem. I'm constantly having to figure out how to not run into clamps. In theory I have almost all the parts to build a big unit (3'x4' work area), but I'm having to evaluate whether I'm up for the work - it's competing with a lot of other stuff at the moment. Buying a new unit would be $2k+ though (although I could sell my current unit to recoup some of that), which is tough to face when I've already spent the $$$ on upgrade parts.

Got the STL. I got a successful tiny sample print from my printer over the weekend, so I think I'll give printing the waveguide a shot. I haven't really had to work with supports much in the past, so it'll take a bit of experimentation to see whether I feel comfortable trying to print mouth-up. I suspect mouth-down is likely to be easier, but then you probably end up with supports in the flare requiring more clean-up work.

My very preliminary measurements of my CNC'd waveguide for the DA25Tx went pretty much as expected - not awful up to 10k but then fell apart. So, that will be an ongoing design process, and seeing how much work some folks have put into getting it 'just right', one that ultimately might get shelved. I like what the DA25Tx brings to the table, but if a waveguide is needed for that project it's highly unlikely that I'll come up with anything close to what augerpro achieved with the SB26ADC/CDC.

I have a bunch of 3d printers being run by an acquaintance in the building I live in for reasons I don't totally understand; they are form 3 resin printers and their bed is just big enough to do the waveguide we designed. For a 4" waveguide I fully expect the sb21 sdc / augerpro waveguide to work perfectly - his results and my simulations seem to line up well.

 

[617]

For me it makes no sense to omit contemporary possibilities. My recommendation is, to aggressively bring these to use. And if it was only for the final integration into the room and/or with subs.

A digital EQ is obligatory. As is a measurement microphone. You'll better cut the wood with the toothbrush than to try DIY without these devices. The implementation of digital EQ can be left to the individual: computer / miniDSP / plate amp whatever.

The design could, and from my perspective should, for several reasons work with a passive XO. Only that the focus is directivity and dstortion, and hence linearity is left for the said EQ. Why not accept a +6dB somewhere if it is easily corrected? Baffle step, who cares?

All what comes next is already lost in personal preferences, right I've seen somebody asking for a 200$ woofer … to be combined with 15$ tweets, which are easily but severely upgraded by some other at 23$.

Good narrow dispersion design ( no affiliation ):

https://heissmann-acoustics.de/en/disco-m/

I'm not quite sure what you're advocating, but a fully passive design which just does the crossovers and makes heavy use of global EQ could be an interesting option. I'm designing this system under the assumption that the easiest, most appealing and cheapest way to create this speaker would be using these Dayton DSP amps (testing in progress), but of course there are a myriad of other options, such as outboard amps and dsp, minidsp units, and a whole host of amps. If a hybrid passive/active design is developed (active between woofer/mid, passive between mid/hf) even more options become available.

 

[617]

That really comes down to how well you run the printer. If you keep it in a temp and moisture controlled room with the machine set up for the conditions it's printed in, you would be fine. It's all in the prep.

You could also print it in 2 parts. The faceplate (face up) with only 6mm depth that has mounting nubs that line up to the throat part. Both parts can now be printed solid without using much material.
This also solves fitting a driver to the WG, as the throat can be screwed to the driver before attaching to the WG faceplate. This in turn would allow you to fit the faceplate to the speaker permanently and paint over it if you so wish, reducing diffraction points.

The one thing with Augerpro's waveguides which I dislike, besides the elliptical recess you have to carve for them, is the method of attaching the tweeter. He has placed these 3 nubs on the back of the tweeter which register with the faceplate. Then you use a bar of wood or something screwed to the back of the WG which pulls the tweeter and the WG together. This works I suppose, but the method I developed for the RST28/Visaton waveguide is a bit cleaner:

https://www.audiosciencereview.com/forum/index.php?threads/diy-speakers-with-waveguide.10021/

Everything is screwed together. This necessitates a 'split' in the waveguide, but I think it could work well.

 

[Lbstyling]

I didn't realize how far this got already. Did You ever mention to address the vertical suck outs from interference? If we take spinorama serious, these are part of the early reflections, hence their absence would contribute to pleasure. If DIY doesn't go further than the industry standard of ignorance, what shall it?

Alas, I'm just working on a pseudo coax. You're too early.

What are You aiming for?

I agree the vertical

A good design, that's it, that's all I'm hoping for. I will help where I can, but this is not my build, so I'm not precious over it.

I suggested the BMR 3 inch mid driver to a cheap 3/4 tweeter as they are both very compact, giving the smallest C to C distance we can get. With active X over, steep crossover filters can reduce the null issue further. If it's steep enough, you should be able to reduce it to the point that it doesn't even show with psychoacoustic smoothing applied. Others wish to pursue a 1+5+8 design.
On the active Vs passive front, I think once a design moves to the point of measuring the drivers on a baffle, the choice will be easier to make. Some designs work passively, some just don't.

Psudo coax?? Interesting! Do tell!!

 

[GelbeMusik]

I suggested the BMR 3 inch mid driver to a cheap 3/4 tweeter as they are both very compact, giving the smallest C to C distance we can get. ... Others wish to pursue a 1+5+8 design.

That comes close to what I consider a humble speaker for real music lovers.

The Dayton RS225 showed very good results with all the stress tests I usually apply. The Tymphany TC9 did the same, from 400Hz on. The TC9 may benefit from selection, since roughly half of it go down even lower.

Psudo coax??

Four TC9 embracing a miniture AMT (see Adam Audio). The four exhibit a deep null at around 2.5k, which is filled in off axis by the AMT. Looks promising, but still has to be realized.

Regarding steep XO, did You consider the Cauer topology?

 

[617]

That comes close to what I consider a humble speaker for real music lovers.

The Dayton RS225 showed very good results with all the stress tests I usually apply. The Tymphany TC9 did the same, from 400Hz on. The TC9 may benefit from selection, since roughly half of it go down even lower.



Four TC9 embracing a miniture AMT (see Adam Audio). The four exhibit a deep null at around 2.5k, which is filled in off axis by the AMT. Looks promising, but still has to be realized.

I'm sure you're familiar with the German fellow on DiyAudio who does the pseduo coaxes? The bmrs are game changers for those designs.

 

[GelbeMusik]

I'm sure you're familiar with the German fellow on DiyAudio who does the pseduo coaxes? The bmrs are game changers for those designs.

Alas, I'm not. Would You mind?

 

[TimW]

I'm designing this system under the assumption that the easiest, most appealing and cheapest way to create this speaker would be using these Dayton DSP amps (testing in progress)

What kind of performance would you need to see from these amps to use them on this project? I wouldn't be surprised if they have a SINAD of 70 or less. But that wouldn't stop me from using them.

 

[Lbstyling]

Augerpros waveguided SB 21 does measure exceptionally smoothly, however, it is 5db down by 30 degrees off axis at over 5khz. Is this wide enough of a dispertion pattern? While narrow is my audiable preference, toole does not support this as preferable for the majority of ppl.

Food for thought.

https://www.diyaudio.com/forums/multi-way/318190-source-waveguides-cnc-3d-printing-11.html

 

[HammerSandwich]

Alas, I'm not. Would You mind?

FoLLgoTT at DIYA, and see his project page.

 

[617]

FoLLgoTT at DIYA, and see his project page.

That guy is a maniac/genius. Thanks for finding the link I had lost it.

 

[617]

What kind of performance would you need to see from these amps to use them on this project? I wouldn't be surprised if they have a SINAD of 70 or less. But that wouldn't stop me from using them.

I don't really care about the Sinad unless it is truly abysmal, I just want to make sure the rated power is reasonable before it starts going through the roof. I think the reference design from TI gives 80W into 4 ohms before things get too bad.

If it's powerful and has no obvious noise I'm happy for the price. If you want better amps Dayton sells the dsp PCB as a standalone unit, so you could pair that with icepower modules or whatever you like.

 

[HammerSandwich]

This reminds me that you need to consider the amp's Vrms in your driver selection.

A driver's impedance peak can keep its power draw fairly low, making voltage the limiting factor. If you're looking only at a power limit, this can fool you. The earlier SPL estimates were based on Xmax, right?

Now that Vituix has multiple overlays in the enclosure tool, I can build some charts.

 

[HammerSandwich]

That guy is a maniac/genius. Thanks for finding the link I had lost it.

Incredibly impressive projects! I was blown away by his outdoor measurement rig that combined an in-ground infinite baffle with a rotating mic frame.

 

[617]

This reminds me that you need to consider the amp's Vrms in your driver selection.

A driver's impedance peak can keep its power draw fairly low, making voltage the limiting factor. If you're looking only at a power limit, this can fool you. The earlier SPL estimates were based on Xmax, right?

Now that Vituix has multiple overlays in the enclosure tool, I can build some charts.

I believe all my simulations are xmax limited. Xmax is defined in different ways but I would argue it's more of a 'hard limit' than power handling, where a woofer might be able to do 80w continuous and 1000w for a millisecond.

If you'd like to do some more detailed woofer comparisons that would be a good idea. What data about the amp performance would you like to see?