DIY speakers, need advice

[wencheng]

DIY speakers, need advice
This is a loudspeaker I designed, machined with 240mm diameter aluminium round pipes, 8 x 4.5" woofers, 1 x 4" KEF mid-tweeter, cabinet sealed.
Since I know very little about acoustics, please let me know if you have a better opinion, it would be appreciated.
Thank you very much for your comments

 

[voodooless]

It certainly looks impressive!

It seems like this could be quite an interesting build. It certainly should be very flexible, especially is you DSP the coax, front, sides and rear into separate channels. You should be a able to make some kind of sound steering and control directivity until quite low down, like D&D or Kii.

I would probably make the rear woofers bigger so they can do subwoofer duties. It’s probably a good idea to have the coaxial in its own enclosure. Make sure the coax to cilinder transition is smooth (see KEF Blade or LS60). Maybe rear mount the woofers so that all holes can be round? Not sure if that would be easy to fabricate?

 

[alex-z]

Mid-range will needs its own air volume so the woofers don't act against it.

The enclosure shape and driver layout is fine, although typically larger woofers are used to get more cost effective bass output.

You will want a DSP crossover to control the radiation pattern. Combined with class D amps you should be able to shrink the electronics cabinet quite a bit, make the entire cabinet circular.

 

[wencheng]

This is a reference to the KEF LS60, maybe I disassemble the amplifier and reassemble it into the cylinder below

 

[kemmler3D]

Looks serious. Would need to know more about the goals and intent before offering any advice.

I would just say for now that if you don't know much about acoustics / speaker building then an LS60 style design will be pretty tricky. They do a lot of fancy stuff with the crossovers to get everything to mesh well.

e: Based on your other post, I assume you have LS60 parts on hand and you're building a speaker to make use of them... if you aren't using all the same drivers it will not work the same. You could do something of your own by removing the digital / DSP section of the LS60 electronics and only use the amps, then do your own crossover?

 

[GM3]

Integrating the woofers to the cylinder might be a challenge, how would you attach the the drivers to the alu? (flat to curved isn't easy!) And will you create some sort of transition for smooth baffle integration? Though the integration part might be near insignificant, extrusions and sharp edges tend to be minimized to reduce diffraction, so at least for the coaxial and front woofers I'm guessing it would be worth it to do so.

Looks like cylinder should work well, but I'd double check given diameter, sometimes things aren't very intuitive!

For the crossover/amp, why so large btw? Personally, I'd just keep them separate from the speakers, which would allow maybe either a one piece cylinder or monitor+base, would probably be sleeker and easier!

Lastly, design is obviously omnidirectional, would that be really better than a sort of line array with woofers in front? Front drivers would allow cutting a flat front baffle for all the drivers. So the front baffle could be a flat alu sheet, which would allow drivers to be mounted flat, likely would make the build again easier? Plus as mentioned the sealed compartment inside the cabinet to seal the coaxial driver, could attach the front baffle. So for construction, the entire front flat baffle could be removed in one piece, then screwed to the cylinder. Something like this; for 4 woofers; other 4 could be in the bottom cabinet:

Check out the driver arrangements here; https://www.speakerdesignworks.com/about-1 Ex; Uluwatu. Obviously not omnidirectional, but as kemmler mentioned given the challenges of omnidirectional design, if this is your first rodeo, going with a more traditional driver arrangement would likely be much easier?

For 8 drivers, as above, 4 could on top cabinet and the 4 others could be on the bottom cabinet, but that would mean that you would need 2 ports, one for top cab and one for bottom cab, unless it's one cabinet, then 1 port as Uluwatu would work too.

I don't see any port in either of your designs, so that would be something to factor too, unless you're planning a sealed design!

 

[voodooless]

Integrating the woofers to the cylinder might be a challenge, how would you attach the the drivers to the alu? (flat to curved isn't easy!)

3D printing adapters would be an obvious and relatively simple option.

 

[wencheng]

Integrating the woofers to the cylinder might be a challenge, how would you attach the the drivers to the alu? (flat to curved isn't easy!) And will you create some sort of transition for smooth baffle integration? Though the integration part might be near insignificant, extrusions and sharp edges tend to be minimized to reduce diffraction, so at least for the coaxial and front woofers I'm guessing it would be worth it to do so.

Looks like cylinder should work well, but I'd double check given diameter, sometimes things aren't very intuitive!

For the crossover/amp, why so large btw? Personally, I'd just keep them separate from the speakers, which would allow maybe either a one piece cylinder or monitor+base, would probably be sleeker and easier!

Lastly, design is obviously omnidirectional, would that be really better than a sort of line array with woofers in front? Front drivers would allow cutting a flat front baffle for all the drivers. So the front baffle could be a flat alu sheet, which would allow drivers to be mounted flat, likely would make the build again easier? Plus as mentioned the sealed compartment inside the cabinet to seal the coaxial driver, could attach the front baffle. So for construction, the entire front flat baffle could be removed in one piece, then screwed to the cylinder. Something like this; for 4 woofers; other 4 could be in the bottom cabinet:

View attachment 418636

Check out the driver arrangements here; https://www.speakerdesignworks.com/about-1 Ex; Uluwatu. Obviously not omnidirectional, but as kemmler mentioned given the challenges of omnidirectional design, if this is your first rodeo, going with a more traditional driver arrangement would likely be much easier?

For 8 drivers, as above, 4 could on top cabinet and the 4 others could be on the bottom cabinet, but that would mean that you would need 2 ports, one for top cab and one for bottom cab, unless it's one cabinet, then 1 port as Uluwatu would work too.

I don't see any port in either of your designs, so that would be something to factor too, unless you're planning a sealed design!

I got the amplifier assembly of the LS60 wireless speaker in the thrift market and repaired it,
I will use this amplifier to DIY speakers
Thank you

 

[wencheng]

3D printing adapters would be an obvious and relatively simple option.

I would ask about the cost of 3D printing
Thank you

 

[kemmler3D]

I would ask about the cost of 3D printing
Thank you

Very cheap if you have the skills and equipment already... if someone else does it for you, cost varies.

I will use this amplifier to DIY speakers

I think you should consider using some larger drivers (8" or 10") for the bass. SPL / output varies depending on cone area, and a single 8" driver has 4x more area than a 4" driver. Of course this is more of a problem when using a cylindrical housing, but if you can machine different shapes then you could solve this.

 

[OldHvyMec]

WOW, that is a lot of work. You've already built it? Omni directional at the very least. Is the tweeter sealed?

A single tweeter crossed at what XO point? 2-way?

Regards

 

[voodooless]

I got the amplifier assembly of the LS60 wireless speaker in the thrift market and repaired it,
I will use this amplifier to DIY speaker

How will that work? It’s specifically made for the LS60 and can’t be customized. It would also lack channels for your project.

 

[wencheng]

It's a three-way amp with a mid-bass at 390Hz and a mid-treble at 7khz, that's just my guess, I connected it to the tweeter, midrange speaker, woofer and it seems to get a good sound

 

[voodooless]

It's a three-way amp with a mid-bass at 390Hz and a mid-treble at 7khz, that's just my guess, I connected it to the tweeter, midrange speaker, woofer and it seems to get a good sound

It’s made for only a 3-way, while your design is at least a 4-way, possibly a 5-way. The DSP is tailored to work with the setup and specific units of the LS60 in terms of gains, EQ and slopes. The result will be be sub-optimal at best.

 

[kemmler3D]

It's a three-way amp with a mid-bass at 390Hz and a mid-treble at 7khz, that's just my guess, I connected it to the tweeter, midrange speaker, woofer and it seems to get a good sound

The crossovers are spec'd to be at 340Hz and 3.1kHz.

I think you can re-use the amps if you know what you are doing, but as @voodooless says the crossover and DSP are heavily customized for the specific design of the LS60. You will need to bypass the digital section of the amp module and do your own crossovers if you want good results.

 

[wencheng]

It’s made for only a 3-way, while your design is at least a 4-way, possibly a 5-way. The DSP is tailored to work with the setup and specific units of the LS60 in terms of gains, EQ and slopes. The result will be be sub-optimal at best.

It's internally connected

 

[wencheng]

The crossovers are spec'd to be at 340Hz and 3.1kHz.

I think you can re-use the amps if you know what you are doing, but as @voodooless says the crossover and DSP are heavily customized for the specific design of the LS60. You will need to bypass the digital section of the amp module and do your own crossovers if you want good results.

I don't have any plans to bypass his digital channel right now,
Since I need to use his wifi and DAC and wisa, it will be very difficult

 

[AudiOhm]

My thoughts, start small, work your way to the pinnacle of speakers in your mind.
2 Way, 3 way, bass reflex, etc.
You will learn a lot on the way...

Ohms

 

[kemmler3D]

I don't have any plans to bypass his digital channel right now,
Since I need to use his wifi and DAC and wisa, it will be very difficult

Can you reprogram the DSP?

Using pre-existing crossovers (and various other filters the LS60 is using that we don't know about) will usually lead to bad results. The LS60 has dynamic compression enabled by default, for example. This is designed specifically for the drivers in the LS60... there's no way it can work properly on a random set of other drivers.

It is like trying to wear clothing that is custom tailored for someone else. Maybe you can put them on, but they will look bad.

If you can't change the DSP then my strong recommendation is to forget the current design and copy the LS60 as closely as you can.

 

[Mr. Widget]

Sorry to do a car reference, but this seems a bit like you found and repaired a Ferrari engine and now you want to build a Ferrari... without a lot of experience you would be better off buying a Honda.

That said, you will learn a lot and may have a lot of fun.

The specialized knowledge required to equal the LS60's performance in a new configuration is significant.

It is like trying to wear clothing that is custom tailored for someone else. Maybe you can put them on, but they will look bad.

Unless you are an experienced tailor.