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Active DSP Speaker Project?

M

MartinC

pfm Member
Looking at a new DIY project for 2020, and active speakers come to mind. Having run active Kan's many moons ago and being impressed by how in my opinion they transformed the Kans, a project using newer technologies sounds interesting.

Hypex now produce class D NCore plate amps with inbuilt dsp, so using these with a 2 or 3 way DIY speaker seems a logical option. I am currently running Ergo IX's passive and was also considering building a second set and incorporating the Hypex plate amps, however they are too large to be accommodated in the Ergo cabinet, so would require a significantly modified box. Due to that I am leaning towards a 3 way with a 4" mid driver and perhaps a 8" bass unit.

The project is still very tentative, but I am wondering if anyone else has embarked on a similar build?
 
Yes! I built some speakers using some 'LS 3/5a" cabinets from Moldova (via eBay). At first I used some old Focal bass units and various tweeters, but the bass units started playing up due to issues with the surrounds, so I decided to start again, using Monacor bass and tweeters, which were not expensive, and seem to be very good. Inside each speaker is a B&O IcePower stereo module (I think 20W per channel, maybe more). Between source (Squeezebox touch) I have a MiniDSP HD 2 in 4 out module, with remote volume control. Set everything up with REW. I equalised the bass units to give remarkable bass extension and set the crossover frequency. The tweeter didn't really need much EQ. I then installed them in my kitchen. I then ran REW in situ and applied an overall correction to give a 'room curve' response at my listening position. Final result is a superb full range like sound, although with limited overall volume capacity - but they are mainly used to listen to Radio4 not death metal. Resolution is superb, and they tonally match my ML Summits, so we can move from one room to another without any sudden change of sound. Go for it!
 
The plate amps are great, I sell loads of them on my site, bit as you say they are quite big. I've had some enterprising customers disassemble them and rebox into external crossovers. I love when people take this sort of extreme route. I normally do my active speaker development with either a PC using the audio engine in Jriver which is very flexible, if a little clunky, and my Motu 8a multi-channel interface, or a mini DSP 4x10 which is really user friendly but maybe not so flexible. Luckily as I sell multi channel Ncore amps, I've enough spare modules kicking around that both of these set ups can permanently have 8 amp channels each. This way it's really easy for me to be testing and playing with development speakers or customer builds or test etc and then easily move speakers to the lounge and just bring the files from one setup to the other. Works well for smaller speakers as everything is off board, I've rocked active Ergo IXs this way in the past, in fact, I took them to Salford one year.
 
Thanks for the replies, I am encouraged!

What was the response to the active Ergos ? I know that James was fairly sceptical that going active would provide any sonic benefit.

Regards
 
MartinC said:
Looking at a new DIY project for 2020, and active speakers come to mind. Having run active Kan's many moons ago and being impressed by how in my opinion they transformed the Kans, a project using newer technologies sounds interesting.

Hypex now produce class D NCore plate amps with inbuilt dsp, so using these with a 2 or 3 way DIY speaker seems a logical option. I am currently running Ergo IX's passive and was also considering building a second set and incorporating the Hypex plate amps, however they are too large to be accommodated in the Ergo cabinet, so would require a significantly modified box. Due to that I am leaning towards a 3 way with a 4" mid driver and perhaps a 8" bass unit.

The project is still very tentative, but I am wondering if anyone else has embarked on a similar build?
Click to expand...
Perhaps you can take a look at this page to get some inspirations. The quality of the used parts and the kits are outstanding. But not cheap ;-)
have fun...
 
Funnily enough I didn't actually play them at Scalford in the end as the room was huge, I had 2 other massive pairs of speakers so the were not needed.

I ran them active for ages, they worked really well, active done right is almost always better, especially if you can go linear phase. Much easier to tune to your room/taste too.
 
Thanks for the link Fred, the smaller speakers look exactly like the somewhat modified Ergo IX's I was considering, they use the same bass driver and with a cabinet just big enough to accommodate the plate amp. Their site is interesting and shows a lot of options for configurations.
 
Those plans outlined at Aos.Lautsprecher are good plans and a good use of the Hypex plate amps.

Stefan
 
MartinC said:
Thanks for the link Fred, the smaller speakers look exactly like the somewhat modified Ergo IX's I was considering, they use the same bass driver and with a cabinet just big enough to accommodate the plate amp. Their site is interesting and shows a lot of options for configurations.
Click to expand...

orangeart said:
Those plans outlined at Aos.Lautsprecher are good plans and a good use of the Hypex plate amps.

Stefan
Click to expand...
Glad I could help.
I got a big speaker from him. He knows his stuff!
 
Well, the idea morphed into an active subwoofer with DSP! - Having hooked up an old sub we had used with a home theater set up, augmenting the Ergo's with a little low bass really added something, especially at low listening levels. So, project is underway!

Driver: 10" Dayton Audio RSS265HF-4
Amp: Hypex FA251
Cabinet: Sealed, around 36 liters
Construction: External side walls 0.75" Baltic birch, baffle 1.5" MDF, rear inner wall 0.75" MDF, rear outer wall (for amp enclosure) 0.5" MDF, internal baffles/stiffeners a mix of MDF and baltic birch.

Cabinet in work:


script>
 
Thanks guys, lesson: you can never have too many clamps when building speakers - the Ergo IX's were far easier being a lot smaller, a degree or so off on assembly makes far more difference on this beast!
 
Almost there! - veneer applied, rear wall attached and Hypex amp installed, front baffle glued in.




Was hoping for a better wood match with my Ergo's but this lot of walnut veneer is a fair amount darker than the prior one.
 
Complete, shakedown to break it it, so far so good - adding it to the little Ergo's I like a lot. The Hypex amp is incredibly configurable, been playing around using REW and a calibrated mic, but need to way for a longer USB cable to make changes real time and set the response with the sub in the location I want it. Unfortunately my laptop is a Mac and the Hypex filter software is PC only.



Excuse the nasty carpet :eek:, temporary location in my office while burning it in.
 
Very smart, and quickly put together! Couple of questions...
Your own design?
and what method did you use to apply the veneer?
 
Yes I did the design, but got ideas from the web. The required internal volume was calculated using the driver manufacturers spec sheet and neat little program called Box-Port Design. Despite the name it allows you to select sealed box as well as ported. As the sub is for music not movies, I aimed for well controlled response as opposed to going as low as possible. The Hypex amp also allows you to add some LF boost if you want to (still experimenting with the best settings).

I used wood glue / hot iron technique for the veneer, its pretty forgiving. Apply a few coats of PVA type wood glue to the veneer backing and the cabinet, wait till its dry to the touch, then place the veneer on the surface and iron it on using an iron on the cotton setting. I used a paper backed veneer which is easy to work with.
 
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