Converting old pair of speakers to actives

[The Vinyl Adventure]

Since I have had such overwhelming succes with my Adams I thought I might see if I could do something similar with my Dynaudio a42's
They are really tatty so I don't mind taking them apart... it seems as though if I got one of these

http://www.behringer.com/EN/Products/CX2310.aspx

And found out the crossover frequencys of the dyns, I could use my hlly90 and my bantam and bin the passive crossovers...

Am I right, or am I confused?

It would only cost me the £60 for the behringer crossover and might be fun finding out the difference in sound quality

Your more knowledgeable than mine thoughs please :)

[Puffin]

I am sure someone will correct me if I am wrong, but I think you can use it to run the speaks actively. You will need an amplifier for each drive unit, a stereo (or monoblocks) for the bass L & R and the same for the treble. If you have a 3 way speaker the Behringer will allow you to control a mid-range driver as well. You would need more amps though.

So far as the crossover frequencies are concerned, you could start with those reccomended by Dynaudio and then tweak by ear from there. Sounds like great fun.

I would have thought that the bass will be much punchier.

Manual here :-

http://www.behringerdownload.de/CX2310/CX2310_ENG_Rev_A.pdf

[The Vinyl Adventure]

The other thought I had was to use your gainclones for the bass and the hlly for the trebble... That could be interesting, but I wasn't sure if using that far different amps would be a good idea?

[The Vinyl Adventure]

(the dyns are 2 way)

[Puffin]

I have edited my first post to add a manual for the Behringer. What is puzzling me a tad is that the crossover frequencies (Treble) maxes at 9.3kHz. However it is said that the frequency response is said to be 5Hz to 60kHz?

Different amps shouldn't be a prob. Try it.

[The Vinyl Adventure]

Nice one!...
It's not exactly an expensive experiment eh?!
Wish me luck...
Just gotta work out what cables I need now...

Another question ...
There is a difference in power output from the gc's compared to the hlly ... Il be controlin the over all level before the crossover with my caiman ..

The hlly has a volume control, but will i need to find a way to control the level of the gc amps?

[Puffin]

but will i need to find a way to control the level of the gc amps?

I would think so, unless the Beh has a pre-amp facility?

Just seen this :-

"Indivual output levels controls for all bands"

[Macca]

I've got some old DIY floorstanders in 55 litre cabs and have in the past idly considered making them active (I've got enough spare amplifiers) so following this with interest.

[The Vinyl Adventure]

What is puzzling me a tad is that the crossover frequencies (Treble) maxes at 9.3kHz. However it is said that the frequency response is said to be 5Hz to 60khz

Yeah? Maybe that's where the adjustment goes up to? ....I have no real idea what I'm talking about :lol:



I would think so, unless the Beh has a pre-amp facility?

Just seen this :-

"Indivual output levels controls for all bands"

That's that problem solved then!

[The Vinyl Adventure]

I've got some old DIY floorstanders in 55 litre cabs and have in the past idly considered making them active (I've got enough spare amplifiers) so following this with interest.

If you have the amps and speakers the behringer is so cheap it's worth a go I reckon... Il let you know how I get on... Just gotta find the money for the behringer and I'm gonna have a go!

[The Vinyl Adventure]

Is there a way to measure the output from the different amps to make sure they are the same?
If they were different that would surely make it a pain in the arse to set up the crossover frequencys correctly?

[The Grand Wazoo]

The voltage gain figures need to be matched Hamish, that's the figure you need to know. My two Levinson amps both have a gain of 26dB, that's why they work well together in my bi-amped set-up. Otherwise (as a layman) you have to fiddle about with setting levels by ear, which is do-able but you never know for sure if you've got it right - you often end up with too much bass than is strictly correct.

[Macca]

Otherwise (as a layman) you have to fiddle about with setting levels by ear, which is do-able but you never know for sure if you've got it right - you often end up with too much bass than is strictly correct.

Hours of fun, though:)

[The Vinyl Adventure]

can i just measure the output from the power amps with a multimeter?
if so, how? some sort of test tone? and what am i measuring? volts?...

this is fast getting more complicated the more i think about it ... should be fun though?
maybe i should just get a second hlly .... or make another pair of gain clones?

[The Grand Wazoo]

I think that the fact that the Behringer has individual output levels for the various bands and that one of your power amps has a pot would allow you to find a way to work with it OK. - Maybe just one extra level of fiddling!

[The Vinyl Adventure]

..... make another pair of gainclones... now that sounds like it could be fun ...

Rob, could you point me to the place you got these gc bits from... if i recase the pair i have now into a single case then i will have a spare transformer for a second pair in a second case....

this is getting more expensive too now.... but it is giving me a few options to play with ...

i guess a second hlly would be cheaper though?

[Stratmangler]

can i just measure the output from the power amps with a multimeter?
if so, how? some sort of test tone? and what am i measuring? volts?...

this is fast getting more complicated the more i think about it ... should be fun though?
maybe i should just get a second hlly .... or make another pair of gain clones?

Unfortunately the gain of the amp has sod all to do with what comes out of the back end.

Doubling up on the HLLY would work - same for the Gainclones.

[The Vinyl Adventure]

I think that the fact that the Behringer has individual output levels for the various bands and that one of your power amps has a pot would allow you to find a way to work with it OK. - Maybe just one extra level of fiddling!


yeah, im sure i could figure it out... im going to have a go this way and then look into getting matching amps i think....

[The Vinyl Adventure]

Unfortunately the gain of the amp has sod all to do with what comes out of the back end.

Doubling up on the HLLY would work - same for the Gainclones.

so you dont think my current idea is a goer?

[Stratmangler]

so you dont think my current idea is a goer?

If you have the same gain structure from the 2 sets of amps then yes.
Otherwise, probably not.

The power output of the amps is not a major issue; matching the gain is very much an issue.

[Macca]

If you have the same gain structure from the 2 sets of amps then yes.
Otherwise, probably not.

The power output of the amps is not a major issue; matching the gain is very much an issue.

If the active crossover provides adjustment for both frequencey response and output level can the different gain levels not be matched by trial and error adjustment of the output level? Or am I missing something?

[The Vinyl Adventure]

ok...

il look at getting another hlly too then.... .....

or...

im wondering if i already have a "LM3886 Dual Mono Kit"
i could just get another pair of "amplifier boards"
and run 2 amp boards from one power board each?

http://www.chipamp.com/lm3886.shtml

(i have a dual mono 3886 pair rob made)

[Stratmangler]

If the active crossover provides adjustment for both frequencey response and output level can the different gain levels not be matched by trial and error adjustment of the output level? Or am I missing something?

You're still going to have an issue with the gain ratio of the two amplifiers.
You'll be able to match them at one volume level, but as soon as the signal level changes the goalposts have moved.

[Macca]

You're still going to have an issue with the gain ratio of the two amplifiers.
You'll be able to match them at one volume level, but as soon as the signal level changes the goalposts have moved.

Got it! So I was missing something. No change there, then...:(

[smurfbrain]

Hamish i have a already built board based on 3886 which is surplus to my needs.
if you want it its yours. can post a photo later this afternoon. just let me know.

[The Vinyl Adventure]

That would be great!!
Can I see a piccy?

I think id like to go down the gc route... They sound a bit smoother with the dyns

[smurfbrain]

there you go.

[Puffin]

Hamish. Sorry I have been out enjoying myself this afternoon and missed all the action on your posts!!! Now I am drinking wine, which means I type a little bit more slowly!

If I were you I would try to get some of the same boards as are in the "Bread Bin" or sliced bread as it is now! They were being discounted by BrianGT (see strap line on Diyaudio site) not sure if they still are. You get all the bits you need to make the amps. You can use one of the transformers from the "crumbs" I made and save money!

[Reid Malenfant]

There is or possibly could be something here that you haven't considered ;)

Passive crossovers aren't just frequency dividers, they tailor the response in quite a few cases. For instance, most bass midrange drivers tend to have a rising response in the upper midrange. In other words they get peaky :( Often the crossover to the bass unit is built so it deliberately starts rolling of early but more gradually than you'd think by simply looking at the order of the network. By order i mean 12, 18 or 24Db per octave.

Depending on the order of the Behringer crossover you are considering it might well be worth dropping the crossover frequency from the bass to tweeter. If it happens to be 24Db per octave then i'd definately recommend it. 2KHz should be fine for just about any 1" dome tweeter as the usual resonance is about 1KHz & with 24DB per octave you'll cause no damage at all. If it's 12Db per octave you may run into difficulties if the afore mentioned bassmid driver tends to have a rising response :scratch:

[Alex_UK]

Thanks everyone for the responses - I think I understand the theory a little better now.

[DSJR]

Naim didn't ever eq their active crossovers and this is one reason why Naim-active 'Briks and SBL's (for example) had a rising midrange response for that all important pr@t factor...

Hamish, you ought to invest in some software plus mic so you can see what you're doing on-screen. At least you have the Adams as a reference.

[The Vinyl Adventure]

there you go.

cheers for the offer... you hang on to them.. im going to get some that are the same boards and bits as what i have already

cheers again

[smurfbrain]

your welcome Hamish. anyway i think i have found the use for it:eyebrows:

[The Vinyl Adventure]

if i use a hlly 90 ould i do use the left channel of each amp for high and the right of each amp for low... or should i wire it so one amp only drives low frequency and the other drives highs?...

[Reid Malenfant]

I'd do the first option ;) Far greater stereo channel seperation for one & also both amps will be loaded more equally rather than one doing low power to both tweeters & one higher power to both bass/mids :)

[The Vinyl Adventure]

Thats actually the oposite of what I expected to hear.. But ok, il give it a go... When I have the bits anyway... Just bought the crossover today, so one step closer :)
Just gotta get some money together for a second hlly90 or chipamp 3886 kit now

[Reid Malenfant]

Well if you think about it the individual amps must have a reasonable channel seperation or stereo would become muddied. Effectively the stereo seperation will become seperation between the two crossovers & in any decent amp it must be at least 70Db. That's more than enough for bass/treble seperation :)

It means you have both amps doing the same kind of load so they'll last, rather than one doing both bass channels (possibly loads of power & less amp life) & another doing treble duties (lasts forever).

I was simply thinking about the best use of the power supply for the application, this way you have plenty of power reserve & a more than good enough channel seperation.

Don't take my word for it, i'm sure others will be along with differing opinions, it's the way i'd do it though :lol:

[The Vinyl Adventure]

I guess that all makes sence... I hadn't really thought about it :) ... I don't really know what I should be thinking about... I'm just sorta winging it ... All part of the fun
Cheers for the help though :)

[smithy]

Might be more cost effective to try a big amp passively rather than activating with two little amps.With a two way there isnt a big bass inductor to deal with maybe activating would be of limited benefit.Get a pro-amp or two with gain controls eg Crown K1 or K2 and have a play.

[The Vinyl Adventure]

Nah, that defeats the object... I'm just tinkering, not really trying to achive anything specific :)... The active crossover has just cost me about £30 and the other amp £70-£100 so it's no big fork out of cash and I'm just doing it a little bit when I have a few ££ spare ... It's about the fun of trying it out rather than anything else

I have read that the crossover frequency is 1.8khz ... Does that sound right?

[Stratmangler]

I have read that the crossover frequency is 1.8khz ... Does that sound right?

That's what I've just read on TNT Audio.

[The Vinyl Adventure]

Ta!
I was just thinking I might give this a go with 2 really cheap t-amps before I fork out any extra cash on anything else too pricey... Any thoughts

[Reid Malenfant]

Ta!
I was just thinking I might give this a go with 2 really cheap t-amps before I fork out any extra cash on anything else too pricey... Any thoughts
My very first active speaker build used ILP HY60 amplifiers (try googling them), i'm not sure if you know these but they are just class B amp modules with built in heatsinks ;)

30W RMS into 8ohms & 60W into 4... I can honestly say i have never been so gobsmacked in my life (except when i installed the Krell DT10 transport). Simple MTM driver arrangement with a bass speaker.

If cheap HY60s' can do the job then by all means try something else before investing heavily ;)

Good luck, i doubt you'll need it though ;)