I'm hesitating on which way would be the simplest and cheapest way to go active on the woofers in a 3-way build, so I'm looking for advice.
Background:
I wanted to try wide baffle speakers 'on the cheap', and to build my first 3-way passive XO speakers. I more ore less copied Troels PMS, but used vifa m21 woofers and m13 mids from a pair of Dali 810 that I had in the garage. After a couple of tries I ended up using Seas DXT tweeters that worked well with the mids (alignment).
A lot of simulation and listening and tweaking has gone in to the XO's (LR2 acoustic slopes), and I'm pretty happy with the overall result. However, with the bass I have not been totally happy. The low woofer/mid XO needed for the wide baffle (abt 350Hz) takes a large coil and this is messing up the woofer response, reacting with the woofer impedance etc. I have tried RCL to remove the woofer resonance impedance peak, parallel resistor with he woofer etc, and it did improve, but recently I tried the woofer with active LP XO (EQ APO in PC) and it just sounded better. Note, I was still using the passive HP for the mid, only active LR2 LP for woofer. Simulated in Xsim3d and it lined up very well.
I could just leave it like that, but then I'm restricted to use them only with the PC as source. Would be nice to be able to use them with the surround system too.
I can think of these options:
-Fully passive and not be happy with the bass
-Active for woofer/mid and only use PC as source
-Separate amp in speaker driving the woofer, and some passive network from high level signal to the woofer amp.
-Same as above, but some simple DSP solution to filter woofer.
I looked at using Hypex DSP plate amps for the woofers, but they are just too expensive for this project.. I have a few DIY amps and boards that could be built in the speaker boxes to drive the woofers, but for mid & treble, I would like the freedom to use whatever amp I prefer (JLH class A at the moment).
What I'm leaning towards is to use the amplified signal from 'main amp', have some kind of low pass (analog or digital), and feed that to a woofer amp in each box, and still use passive HP for the mid.
Standard LR2 slope will do for the woofer, but would benefit from a little bit of EQ in the 1-2kHz area to get the perfect acoustic slope. Of course DSP with some extra bass tuning possibilities for room would be a nice feature.
How would you do that in a elegant and cost effective way?
Background:
I wanted to try wide baffle speakers 'on the cheap', and to build my first 3-way passive XO speakers. I more ore less copied Troels PMS, but used vifa m21 woofers and m13 mids from a pair of Dali 810 that I had in the garage. After a couple of tries I ended up using Seas DXT tweeters that worked well with the mids (alignment).
A lot of simulation and listening and tweaking has gone in to the XO's (LR2 acoustic slopes), and I'm pretty happy with the overall result. However, with the bass I have not been totally happy. The low woofer/mid XO needed for the wide baffle (abt 350Hz) takes a large coil and this is messing up the woofer response, reacting with the woofer impedance etc. I have tried RCL to remove the woofer resonance impedance peak, parallel resistor with he woofer etc, and it did improve, but recently I tried the woofer with active LP XO (EQ APO in PC) and it just sounded better. Note, I was still using the passive HP for the mid, only active LR2 LP for woofer. Simulated in Xsim3d and it lined up very well.
I could just leave it like that, but then I'm restricted to use them only with the PC as source. Would be nice to be able to use them with the surround system too.
I can think of these options:
-Fully passive and not be happy with the bass
-Active for woofer/mid and only use PC as source
-Separate amp in speaker driving the woofer, and some passive network from high level signal to the woofer amp.
-Same as above, but some simple DSP solution to filter woofer.
I looked at using Hypex DSP plate amps for the woofers, but they are just too expensive for this project.. I have a few DIY amps and boards that could be built in the speaker boxes to drive the woofers, but for mid & treble, I would like the freedom to use whatever amp I prefer (JLH class A at the moment).
What I'm leaning towards is to use the amplified signal from 'main amp', have some kind of low pass (analog or digital), and feed that to a woofer amp in each box, and still use passive HP for the mid.
Standard LR2 slope will do for the woofer, but would benefit from a little bit of EQ in the 1-2kHz area to get the perfect acoustic slope. Of course DSP with some extra bass tuning possibilities for room would be a nice feature.
How would you do that in a elegant and cost effective way?
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For me this would be case with MiniDSP. Of course depends how puristic your ears are, some people say it is not good enough for high end quality.
Crossovers below 500 Hz are always challenging. It is hard to get the measurements right, and it is challenging to handle the rapidly changing impedance and acoustic phase of the mid and woofer. Going to an active crossover solution for situations below 500 Hz is a smart move.
Here are two options:
1) Use an ICEpower 50ASX2BTL (Class D Audio Amplifier with Power Supply Module 1 x 170W, $120) for each woofer. Use a MiniDSP 2x4 ($105) to digitally process the two woofer signals. Total cost 120+120+105 = $345
2) Use a single Hypex FA122 plate amplifier (2 channel 125W x 2, with built in DSP, $385). Mount it in a small box, and let it drive your two woofers. Total cost = $385.
I have been very happy with Hypex. I used a pair of FA253 amps in a 3 way active system. But ICEpower has a really good reputation.
Here are two options:
1) Use an ICEpower 50ASX2BTL (Class D Audio Amplifier with Power Supply Module 1 x 170W, $120) for each woofer. Use a MiniDSP 2x4 ($105) to digitally process the two woofer signals. Total cost 120+120+105 = $345
2) Use a single Hypex FA122 plate amplifier (2 channel 125W x 2, with built in DSP, $385). Mount it in a small box, and let it drive your two woofers. Total cost = $385.
I have been very happy with Hypex. I used a pair of FA253 amps in a 3 way active system. But ICEpower has a really good reputation.
Agree - the basic MiniDSP has 48k/28bit processing, which should be more than enough for woofer signals below 500 Hz.
Technically, minidsp would be ok, I could process only the bass, and do the mid HP in the passive filter. IMO minidsp should be ok for sound quality up to 350Hz even if the volume control is before the minidsp. (If the minidsp is not adding too much delay..)
However, there is a practical problem with cables/amps. I would like to have the woofer amps built in the speakers, and only have one speaker cable going to them + one power cable for the built in amp, so I would need to get two minidsp's to put one in each speaker..
Any similar (cheap) 1channel DSP's?
How about going passive? There is a lot of voltage to spare if I was to use some passive RC-net from high level signal to amp input.
I would like to have only high level going to the speakers, so I could use a switch to switch between stereo amp and surround amp..
However, there is a practical problem with cables/amps. I would like to have the woofer amps built in the speakers, and only have one speaker cable going to them + one power cable for the built in amp, so I would need to get two minidsp's to put one in each speaker..
Any similar (cheap) 1channel DSP's?
How about going passive? There is a lot of voltage to spare if I was to use some passive RC-net from high level signal to amp input.
I would like to have only high level going to the speakers, so I could use a switch to switch between stereo amp and surround amp..
Because of the relatively high crossover point you wish to use (350Hz) you probably will need to use a "full range" plate amp and not a subwoofer plate amp. I would be surprised to find a sub plate amp with such a high crossover point.
The full range plate amp will probably require an external crossover. Some posters have mentioned the miniDSP.
Instead of buying two plate amps, you could use a stereo power amp with the miniDSP. Get a used Adcom e.g. GFA5400 or something like that if you do not have one lying around.
Minidsp 4 x10 or 10x10 has 8 channels at 96/24 , for me I don't feel the need to go for something more expensive
I don't want to go with minidsp since it will complicate things if I want to use the speakers for surround amp and stereo amp. I have no pre out of the front channels on the surround amp, I can only connect to the speaker output. I used to have separate speakers for surround and stereo, but these are so wide that I'm out of space.
Plate amp.. possibly, if I had schematics and could replace components to get LR2 slope at abt 350Hz. However, there is still the cost factor.
Maybe a analog active XO (op-amps) kit that I could use with amp kits I already have? I looked at ebay, but did not find suitable candidates in Europe though? Suggestions?
Plate amp.. possibly, if I had schematics and could replace components to get LR2 slope at abt 350Hz. However, there is still the cost factor.
Maybe a analog active XO (op-amps) kit that I could use with amp kits I already have? I looked at ebay, but did not find suitable candidates in Europe though? Suggestions?
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