My quest for fully DIY active ProAc Response 2.5 clones

[Olli1324]

(I think this is the right place to post this... This is the subforum for tweaks, and I suppose this is a 'tweak', albeit fairly major!)

Ok, so last year I built myself some ProAc Response 2.5 clones (passive crossovers) and am very happy with them. However, I want more.

I have recently been reading a lot about active crossovers and active biamping and have decided that I want to try and actively biamp my ProAc clones.

The first step is choosing the crossover. I am going to use a 4th order Linkwitz Riley crossover, using a PCB from ESP Audio.

Next come the amplifiers.

For the tweeters, I want to use a solid state class A design. This will most likely be Project 3B (again, ESP Audio design).

For the mid/bass drivers, I am going to use the GB150D amplifier from SKA audio.

The pre-amplifier will be P88 with associated power supply (P05) and also the remote control modules (again, all from ESP Audio).

I am in the process of finalising which boards I need to buy and will be ready to purchase them tomorrow/Friday.

Many active speakers have all of the necessary gubbins mounted in the cabinets. At the moment, I am opting to have all of the electronics (active xo, amps and pre amp) in boxes outside of the speakers. As for the number of boxes, I am still indecided. If I wanted to be outrageous, I could have separate enclosures for the following:
[*] 1. Active xo inc. power supply[*] 2. pre-amplifier inc. power supply (AC wall wart to keep the transformer out of the box)[*] 3. P3B power supply[*] 4. P3B amplifiers[*] 5. GB150D power supply[*] 6. GB150D amplifiers[*][*]Making the amps monoblocks with separate power supplies would give rise to a 10 box system. As cool as this would be, case work would be an awfully expensive and intensive. As such, I will probably tuck the power supplies in with their amplifiers. Maybe if I win the lottery I will go through the system putting everything into its own box and see how big a stack I can make

Anywho, I am going to be very busy over the next couple of weeks, so this project won't be getting my full attention but I will be ordering the necessary components and making some decisions about enclosures etc.

The hardest part of this project will be getting the active crossover to integrate well with the speakers (which have fairly complicated passive crossovers). I'm sure it will be worth it though - it should make a stark improvement to the sound over the current passive set up with 45W Marantz PM6002.

I'll document my progress here as much as possible/necessary because I'm sure such a project will be of interest to (at least some) others.

Just to clarify the specification of the system I'm going for...

• - DIY ProAc Response 2.5 Clones
• - 4th order Linwitz-Riley active crossover (ESP Audio)
• - 25W Class A amplifiers on the tweeters (P3B, ESP Audio)
• - 150W GB150D amplifiers on the mid/bass drivers (GB150D, SKA Audio)

Until next time,
Oliver

 

[Olli1324]

Doesn't seem to be as much interest here as on other forums.. Oh well. I will continue to update this thread with progress; it may prove a valuable or interesting resource to anyone who is searching these forums in the future.

Upon other advice, I am going to purchase a commercial active crossover. This will help tune the crossover frequency much more easily. I can then replace the cheap crossover with the proper nice ESP Audio Linwitz Riley one.

I am going to be heading into trouble with non-flat (or at least, not-good sounding) frequency response. Such anomolies are taken care of by using notch filters in crossovers. Of course, I won';t be able to do that here, so I am going to purchase a commercial equaliser. This will allow me to fine tune the frequency response. I can then replace this with a DIY EQ once I know which frequencies are being troublesome etc. (can you guess I like DIY?? )

 

[Olli1324]

Ordered most of the bits now, so am ready to commence the project when in London in June (where I can take photos etc.)

I've ditched the eq idea; if the speakers can't be made to sound decent without using eq, I will just have to start a design from the ground up and find some drivers that work well for this job! That said, the drivers in the ProAcs are extremely good, so they should be able to handle it.

 

[chebby]

Doesn't seem to be as much interest here as on other forums.. Oh well. I will continue to update this thread with progress; it may prove a valuable or interesting resource to anyone who is searching these forums in the future.

I've read it. It is interesting and you should continue posting.

I cannot truthfully say I understand everything but we can all learn a bit from such threads as these.

Please carry on posting updates as you make progress. (Especially the photos when you get that far.)

 

[steve_1979]

Yes please keep us updated as I'm also interested to see how your "tweek" turns out. Hope it goes well.

 

[Olli1324]

I'm glad to hear it; I thought there would be a few lurkers on here watching, based on the popularity of some of the other DIY threads that I have seen on here over the last couple of years.