3 way speakers driven by chip amps?

[radal]

Hi,

My intention was to use one channel of my amp to drive a pair of DIY 3 ways and use a sub on the other channel, but since I'm not sure what the combined impedance would be on the 3 ways I would not want to risk it on my new amp.

My amplifier is an American Audio ELX 3000 pro audio amp that I'm using home.

So I was thinking that I could use a Behringer pro audio active x-over with a sub out to one channel of the amp for the sub and the low out on the other channel for the both woofers of the 3 way.

and I'll send the mid and high out of the x-over to two individual chip amps respectively for the tweeters and mids.

I'm hoping the speakers will sound better with the active crossover compared to the 4 component passive x-over in them right now

Would this work out the way I've been thinking?

Chip amps because they are kinda cheap and I already have this one 2x25W @ 4 Ohm TDA7492 Class-D Audio Amplifier Board Only | 320-332 which I would use for the tweeters

Also I was thinking this one for the mids: 2x100W @ 4 Ohm TK2050 Class-D Audio Amplifier Board Only | 320-334

The 3 way drivers are:

Tweeter (Vifa BC25SC06-02): 50 watts RMS, Impedance 4 ohms, Frequency response 1,350-30,000 Hz, SPL: 96 dB 2.83V/1m

Mid: (Celestion neo. 5 1/4"): 25 Watts RMS, Impedance 8 ohms, Frequency Response 104 to 9,000 Hz, SPL 89.2 dB 1W/1m

Woofer: (GRS 8PR 8"): 65 Watts RMS, Impedance 8 ohms, Frequency Response 40 to 5,000 Hz, SPL 85 dB 1W/1m

The sub woofer is an 8 ohm 250W RMS 15"

 

[jplesset]

I would encourage this experiment. There's really no downside. To get the best sound out of your main speakers, you will want to measure and "tweak" the crossovers to deal with the drivers.

 

[Cal Weldon]

I would invest in a plate amp and do it the regular way. You will be running the channels at different impedance. Not sure it matters that much and maybe others can chime in here.

 

[radal]

thanks, one of my main reasons for wanting to go with chip amps is because of cost, my budget is small especially since I have to pay almost twice the cost here in Trinidad, so plate amps may not be within my budget right now

 

[cT equals piD]

Hi,

My intention was to use one channel of my amp to drive a pair of DIY 3 ways and use a sub on the other channel, but since I'm not sure what the combined impedance would be on the 3 ways I would not want to risk it on my new amp.

My amplifier is an American Audio ELX 3000 pro audio amp that I'm using home.

So I was thinking that I could use a Behringer pro audio active x-over with a sub out to one channel of the amp for the sub and the low out on the other channel for the both woofers of the 3 way.

and I'll send the mid and high out of the x-over to two individual chip amps respectively for the tweeters and mids.

I'm hoping the speakers will sound better with the active crossover compared to the 4 component passive x-over in them right now

In general what you have in mind would result in a loss of stereo reproduction. Also if I'm not mistaken the active crossover has two low out jacks, left channel and right channel.

You could for example use the two channels of amplification of your pro amp to necessarily separately power left and right channel woofers of your 3 way speakers. That is,

active Xover low left ch out----first ch of pro amp--------woofer of left speaker
active Xover low right ch out-----2nd ch of pro amp-------woofer of right speaker

After that, then you need five additional (separate) amplifiers or single channels of amplification to power the sub-woofer, and one each for the pair of mids and pair of tweeters.

Crossing over with an active crossover network at line level is much more involved and expensive than a passive crossover (especially if you want to preserve stereo reproduction!).

This is why so many speaker systems are produced with passive crossover networks, or one of the reasons, anyway.

Regards,
cT

 

[radal]

I might just be willing to sacrifice stereo reproduction... at least until I could buy more amps.

Although my 3 way speakers sound good given its a first time DIY first order passive x-over, I'm almost sure it would sound much better with an active crossover especially since I want to add a sub to the system.

One of my concerns as Cal Weldon pointed out is that my amp will be running with unequal impedance loads from one channel to the other.

Would this be a problem? or could I look at the amp as two mono amps sharing the same enclosure? I've read on the crown amp site that this should not be a problem...I.D.K if it applies to all pro audio amps

 

[kendt]

I have been doing basically the same for some time now.Three t amps, mini dsp driving large OB,s. It works great and your right its a relatively inexpensive way to go active with good results. I recently added a SET amp for mids but still using t amps for subs and tweets. Its a great set up because you can swap amps from mids to tweeters to subs to see what sounds best where as well as experimenting with different xovers.You will learn a lot about how different slopes and xover points affect sound. There is really no down side that I,m aware of.

 

[cT equals piD]

I might just be willing to sacrifice stereo reproduction... at least until I could buy more amps.

Although my 3 way speakers sound good given its a first time DIY first order passive x-over, I'm almost sure it would sound much better with an active crossover especially since I want to add a sub to the system.

One of my concerns as Cal Weldon pointed out is that my amp will be running with unequal impedance loads from one channel to the other.

Would this be a problem? or could I look at the amp as two mono amps sharing the same enclosure? I've read on the crown amp site that this should not be a problem...I.D.K if it applies to all pro audio amps

Most stereo power amps are two mono amps sharing a power supply, ground and enclosure. Unequal loading of the two channel amps of a stereo amp shouldn't be a problem. You would want to pay attention, though, to the lowest load impedance the manufacturer says each amp can tolerate.

Most stereo power amplifiers can handle a four Ohm load, so connecting the woofers of your pair of 3 way speakers in parallel to one channel output of your pro amp should not be problem. If you try it, start at low volume.

If the upper cut-off frequency of the woofer of your 3-way system is fairly low, say below 1 kHz, then giving a mono signal to the woofers most likely would still leave audible stereo reproduction. That's assuming that the mid-range and tweeter of each speaker get a stereo signal.

If one channel of your pro amp drives the a sub-woofer and the other channel is connected to the pair of woofers, then you would need 4 additional amps so that the mid-range and tweeter of each speaker get a stereo (L or R channel) signal.

Depending on the cut-off frequency of your woofer and the type of music that you listen to, the addition of a sub-woofer may or may not make much of an audible difference.

Regards,
cT

 

[sreten]

Hi,

FWIW you need about 10w per channel for the tweeters,
50w* per channel for the mids and 100w for the bass,
and you could do with doubling up the bass units.

rgds, sreten.

* Into 4 ohms.

 

[radal]

Thanks guys

All the amps I intend to use should have ample power especially the Class A/B amp... I saw this thing powered four 15" woofers and two horns effortlessly.

BTW I'm having my cabs built for the drivers and can't wait, all I need to work on is getting the active x-over, I'm looking at the behringer CX2310

 

[jplesset]

Other crossover options include minidsp, or, depending on your source, an old PC with free software can make an excellent player with crossover.

 

[radal]

Other crossover options include minidsp, or, depending on your source, an old PC with free software can make an excellent player with crossover.

I have considered the MiniDSP, does this include a DAC and crossover also, I need to do some reading on it still but it looks very flexible from what I've seen so far

right now my source is a PC but I'm interested in the above quoted text bolded....how does this work?

 

[jplesset]

I found this site several months ago. Richard is far better at this stuff than I am, but I was able to follow his lead, and get it working:
Digital Crossover/EQ with Open-Source Software: HOWTO | Richard's Stuff

My current setup includes an old Toshiba Pentium II laptop (yeah, really old), an inexpensive 7.1 USB sound card, old amps and a subwoofer/satellite setup. The software and hardware are well able to do 3 or even 4 way crossover. Total cost to me $20. MPD is the music player (free). It uses ALSA (free), Ecasound (free), and SOX (free) to do the job. I'm running it on Ubuntu Linux (free)

My results are better than the analog crossover I built years ago, and I'm very happy with the results. PM me if you want more detail, or need help implementing...

 

[radal]

That looks very interesting and cost effective but I don't trust myself putting together something like that...I'm not very tech savy when it comes to computers.

I would prefer an off the shelf solution or something that the average guy could put together I don't know

The miniDSP 2x4 looks good since it's within my budget but I couldn't find any info where the 2x4 version could work in a 3 way mono plus sub configuration

 

[jplesset]

If I could do it, likely, you could. The directions are very good.... For example, to install mpd, the command: "sudo apt-get install mpd" is all you need..... I like being able to control it from a tablet or phone, too.