DIY speaker design, based on ATC SM75-150 mids

Bob Stuart (of Meridian) always maintained that going down the active route means that the demands on power amps are a lot lighter - there's sense in this (although I personally haven't been convinced by the active speakers I've heard with "modular" amps - I guess it's possible to go too far).

 

This company does a modification of that Behringer unit - probably worth having a chat with them if you're thinking of going down that route.

www.audiosmile.co.uk

I've no experience of them personally and no idea if they're any good or not.

 

If you want a passive crossover, then please, please copy a well known design, such as by any of these designers. There are loads more, so ask for more suggestions if needed.

http://www.zaphaudio.com/index.html
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
http://www.humblehomemadehifi.com/

http://www.rjbaudio.com/projects.html
http://highend.projektas.lt/?speakers/1
http://home.versatel.nl/chiararomee/diy/indexeng.htm

If you decide to design your own speakers, then the active route is highly recommended. Using a unit like the Behringer DCX2496 should guarantee success, providing that you can work out how to use it. You can have huge amounts of fun designing a cabinet to suit any fancy, and you should still get it to produce good results.

Three amps are a bit of a pain financially, but you could make one of these very simply (and only use 3 channels). It seems to have good reviews. I love my Tripath amp, though it is a 15W version. See: http://www.autocostruire.com/catalo...d=309&osCsid=d3d34f137084768c48f6351d83278650

 

Some interesting links there - thanks.

Are those amps really any good? Do they give the quoted power? They seem too good to be true! - reinforced by their recommended approach to the power supply, which isn't exactly over-specified in relation to the total power rating.

Paul

 

The Alesis RA500 and RA300 are good amps. Linkwitz recommends them.

 

Hi Paul
I have been away.
"Are these amps any good?" Try asking in the Class D amplifier section of DIYAUDIO. http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=49
My 15W DIYPARADISE Charlize amp is stunning, which is amazing as the board is only the size of a credit card.
I am going to give the audiocosturie amp a go when I try an active system...

 

Over on the Altec/ JBL forums (these guys have some pretty flash DIY speakers) there's a lot of good words being said about the Ashly active analogue crossovers.

http://www.ashly.com/spec-sheets/xr2001.pdf

I've bought an Ashly based on their reccomendation.

The 'general' feel of the US JBL/Altec forums is that at low-mid range prices, analogue active crossovers sound the best.

It's also generally felt that an active analogue crossover like the above (and 3 amps) will give you better sound per pound than a passive.

I'm paraphrasing, but if you want to join the forum and read all the posts you'd get the same feel I'm sure.

Cheers.

 

Chris,

I do hope you document your new speaker build. We never got to see much of what Mike did. Is yours going to be differnt in any way or are you building the same?

 

Hi

Mike's is the inspiration for mine, but his will no doubt be a lot better. He has the best possible TAD/JBL drive units, and mine are a model lower on average. Also, Mike has 3! berning amplifiers - awesome things. The cost of 1 berning amp wil be greater than the cost of all 3 of my amps. His Active crossover is one of the best too.

That all resulted in a really great sound, albeit at the price of a new car. I want to get as close to that as I can, but with a much tighter budget. I hope I do ok.

I've got no doubt that there will be some trials and tribulations on the way, but I'm looking forward to the challenge of it. I've had some great help from some really nice people behind the scenes which never hurts.

viva DIY!

imitation is the sincerest form of flattery, and my Franken-westlakes will probably be as near as I ever get!

 

God some of you are depressing.

If I'd have listened to talk like this I'd have never built anything either. Whether you opt for cheap drivers or expensive drivers you will fail on the first crossover attempt but with all this talk of wastin g money, anyone would think that you only have one shot at this or those expensive drivers suddenly disappear after this first failed attempt.

This isn't as complicated as folks make out. The naysayers mean well but I'd ignore them at this point. It never did me any harm.

The ATC mid is a stunning driver but if I could make a suggestion, go with the 9" ATC SB75-234SC for bass in a 40ltr+ sealed enclosure. I played around with a couple of different bass drivers partnerships and its natural that this driver mates really nicely with ATC own mid.

As for the tweeter I think its good choice but you might want to take a look at the new scanspeak illuminator tweeters and particularly the ones with a small face plate for closer center to center spacing of the mid and tweeter. This is handy since you'll be crossing at 3Khz.

Go with 4th order slopes as a minimum and 500hz plus 3Khz worked very well for me using an R2904-7000 and the ATC mid/bass. You'll need rudimentary measuring equipment such as the ARTA software coupled with a Behringer ECM8000 microphone.

It may be a good idea to prototype the crossover in a cheapish digital unit such as the Behringer DCX2496. This will allow for quick and easy adjustments which you can then confirm and visualise using ARTA and the measurement mic.

These tools as well as time will net you a good loudspeaker

If your happy with DCX2496 you could leave it in the signal chain or build yourself a passive crossover based on the settings you found to work within this unit. There's people, included myself, who would be happy to aid you with that.

Build the cabinets well with thought and care and you'll only need to do that once. The crossover you can have many attempts at with the simple method I've outlined.

 

i'm doing one with the volt 3",seems similar.
i'm no the one who is going to do the xover thought ,for me it's still chinese

 

With thanks to all for their comments - and in particular Shinobiwan for his commensense and encouragement - and offer of help. Indeed I can try again if I'm not happy, bound only to the drivers I've chosen, and at the cost only of more wood.

So, on the basis of advice from everyone who has contributed, and some modelling using Martin King's software, I'm going for a system based on Peerless XXLS830843 bass, ATC SM75-150 and Scanspeak D3004-66000.

The Peerless models almost identically to the B139 in the IMF profile, subject to appropriate damping.

But in fact I'll leave the IMFs alone, and instead try to duplicate the performance in a different shape enclosure, intending it to be more flexible in placement, and hopefully also more 'spouse friendly'.

The mid & tweeter I'll put in a separate enclosure on top, which could avoid the need for 'toeing in' of the main enclosures. Also allows some styling variations.

The setup will be tri-amped - through ebay I've picked up an Alesis ra150 and an Alesis ra300, to complement my existing Musical Fidelity P170, and invested in a new Behringer DCX2496. Once its all set up I can consider whether to go for mods to the DCX to improve it, or go for an analogue active XO having found the appropriate parameters.

Also through ebay while looking for the DCX I've picked up a Behringer DEQ2496, so I can play with room EQ. Part of me thinks this is a good idea, spurred on by the realisation (through Martin King's software) of just how much the room modifies the sound, while part the purist in me - fed by years of 'HiFi' hype' is concerned about the adverse effect of all that electronic compensation. I'll find out which suits me best - and can always sell the DEQ on ebay again if it doesn't help! I just long for the system to sound like my IMFs did when played out of doors!!

I'll let you know how it goes, probably a few months though befor I get it done.

If all that doesn't work I'll try using the new drivers in the IMF enclosure - which I can do non-destructively, replacing the original baffle and drivers if I wish.