Bi-amplification (The next best thing)

[cloth-ears]

Though I would just share my experience with Bi-amping, for those interested. Personally I love it. Once the preserve of the few, active speakers are now easily available to anyone. For less than the price of a special kettle lead or other cables a complete setup can be achieved. You may well have most of the parts needed.

Recently I noticed that a company on eBay selling active crossovers for £35.00, how can you go wrong? All they need is a box and small power supply
The board is based around the OPA2134 op-amp. This is a fabulous little amp with a distortion of 0.00008%. That’s well below the limits of most commercially available test equipment. Stick an Alps pot in the front and you have a world class preamp capable of accepting any line level input

Now you just need two stereo amplifiers. They don’t have to be the same, if fact there is a very good argument to have different amps. Bas/mid drivers and tweeters are chalk and cheese; they couldn’t be more different so why use the same amps to drive both. Also the tweeter only needs about 10% of the power required by the bass/mid driver. You may have a small amplifier (possibly valve) with a sublime treble response but lacks the punch needed to use as a main amp, this would be ideal for the treble. Now all you need is an amp that packs a punch but perhaps lacks treble clarity and you are there.

You can of course use to good amps but I’m trying to show how to do this on a budget

Now the speakers, if they already have the bi-wire option it’s a fairly simple job to bypass the internal crossover. Job done

The advantages of active speakers are many fold. The passive crossover is responsible for much of the intermodulation distortion and high losses. The damping factor is also greatly improved giving a much tighter bass.

So there you have it in a nutshell. You don’t really need dedicated power amps as you can just use the aux input of an integrated amp and having volume controls will allow you to match the different sensitivity's of the bass/mid treble units. At a later time you could bypass the internal preamps altogether and use a couple of Alps pots to achieve the necessary adjustments. The scope is endless and with a bit of experimentation you could end up with a truly outstanding sound for a tiny budget. Give it a try sometime....

[YNWaN]

Just to clarify, what you are describing is usually called active operation in the UK and bi-amping usually means the use of multiple amps but retaining the passive crossover (so one stereo amp feeding the tweeters and one for the woofers - or one channel for the tweeter and the other the woofer - often called horizontal or vertical bi-amping).

[Ali Tait]

Though I would just share my experience with Bi-amping, for those interested. Personally I love it. Once the preserve of the few, active speakers are now easily available to anyone. For less than the price of a special kettle lead or other cables a complete setup can be achieved. You may well have most of the parts needed.

Recently I noticed that a company on eBay selling active crossovers for £35.00, how can you go wrong? All they need is a box and small power supply
The board is based around the OPA2134 op-amp. This is a fabulous little amp with a distortion of 0.00008%. That’s well below the limits of most commercially available test equipment. Stick an Alps pot in the front and you have a world class preamp capable of accepting any line level input

Now you just need two stereo amplifiers. They don’t have to be the same, if fact there is a very good argument to have different amps. Bas/mid drivers and tweeters are chalk and cheese; they couldn’t be more different so why use the same amps to drive both. Also the tweeter only needs about 10% of the power required by the bass/mid driver. You may have a small amplifier (possibly valve) with a sublime treble response but lacks the punch needed to use as a main amp, this would be ideal for the treble. Now all you need is an amp that packs a punch but perhaps lacks treble clarity and you are there.

You can of course use to good amps but I’m trying to show how to do this on a budget

Now the speakers, if they already have the bi-wire option it’s a fairly simple job to bypass the internal crossover. Job done

The advantages of active speakers are many fold. The passive crossover is responsible for much of the intermodulation distortion and high losses. The damping factor is also greatly improved giving a much tighter bass.

So there you have it in a nutshell. You don’t really need dedicated power amps as you can just use the aux input of an integrated amp and having volume controls will allow you to match the different sensitivity's of the bass/mid treble units. At a later time you could bypass the internal preamps altogether and use a couple of Alps pots to achieve the necessary adjustments. The scope is endless and with a bit of experimentation you could end up with a truly outstanding sound for a tiny budget. Give it a try sometime....

Yep, lot of good things to be said about going this way, I've been doing it for several years, using a miniDSP unit.

[cloth-ears]

Just to clarify, what you are describing is usually called active operation in the UK and bi-amping usually means the use of multiple amps but retaining the passive crossover (so one stereo amp feeding the tweeters and one for the woofers - or one channel for the tweeter and the other the woofer - often called horizontal or vertical bi-amping).

Yes, when I mentioned using an “active crossover” and bypassing the “internal crossover” that this was a reasonable clue as to what I meant. My apologies if this confused you

[cloth-ears]

Yep, lot of good things to be said about going this way, I've been doing it for several years, using a miniDSP unit.

The door is wide open to so many at the moment to try this. It's well worth a go for the the budding enthusiast

[YNWaN]

Yes, when I mentioned using an “active crossover” and bypassing the “internal crossover” that this was a reasonable clue as to what I meant. My apologies if this confused you

No, I wasn't confused (I think that's pretty clear from my post). what I think some may find confusing is that the title says bi-amping and then goes on to describe something completely different.

[Clive]

Yep, lot of good things to be said about going this way, I've been doing it for several years, using a miniDSP unit.
You won't have confused Mark it's just the title to the thread is Bi-amplification. Bi-amping (ie passive) can be beneficial but this is more when the amps aren't up to the speaker load. Active operation can be far more beneficial though the rest of the system has to be up to scratch too as it can be quite revealing. Of course a lot depends on the speaker involved. For years I've run speakers using a wideband driver covering 100Hz to 8kHz with the tweeter using a first order xover. The wideband driver does not have a crossover. I run bass actively via a digital xover with room correction DSP. This works well, the midrange has no xover is let's say "unencumbered", it sounds more directly connected to the amp. I have a second set of speakers with a similar bass arrangement but using an Alpair 12P fullrange driver 150Hz upwards. For these speakers I use a capacitor at the input of the amp to cut the bass from the amp and speaker- this is very benficial; it may be due the Alpair cone being small so it unloads the driver of much of the bass.

[cloth-ears]

Semantics. I asked Wikipedia:

"Benefits[edit]

Most audible differences are subtle. If at all noticeable, benefits of bi-amping cannot be realized if passive crossover networks of a speaker system are not removed.[1] Benefits include transients are less likely to cause amplifier overload (clipping) and/or speaker damage, and reduced intermodulation distortion, elimination of errors introduced by low frequency passive crossover, reduction of load to the load presented to the power amplifier, better matching of power amplifier and speaker driver and others.[2]"

[Clive]

Semantics. I asked Wikipedia:

"Benefits[edit]

Most audible differences are subtle. If at all noticeable, benefits of bi-amping cannot be realized if passive crossover networks of a speaker system are not removed.[1] Benefits include transients are less likely to cause amplifier overload (clipping) and/or speaker damage, and reduced intermodulation distortion, elimination of errors introduced by low frequency passive crossover, reduction of load to the load presented to the power amplifier, better matching of power amplifier and speaker driver and others.[2]"
The US use bi-amping as active or passive but usually mean active. The UK has uses the term bi-amping to mean bi-amping of passive speakers and use "active" where there is an active crossover and multiple amps. It's the common usage I've seen over the 45 years I've been interested in this stuff.

[cloth-ears]

The title of the thread says Bi-amplification. That means two amplifiers. I never mentioned the word "passive" in the title. It should be obvious to anyone reading that I’m advocating the use of “active“ crossovers.

Cant people just post a thread for something they think may be useful to others. Why do people get bogged down with semantics? I’m not writing a paper on it for Christ’s sake. Take from it what you will. If only one person finds it useful I’m happy

[Barry]

What Mark is describing is active horizontal bi-amplification. The difference between active and passive bi-amplification and vertical and horizontal bi-amplification is explained here: http://theartofsound.net/forum/showthread.php?5818-Basics-amp-General-Bi-amping-and-Bi-wiring.

Were my speakers capable of having this technique applied to them, I would most definitely go for vertical bi- or tri-amping, using single channel monoblocks.

[Ali Tait]

You won't have confused Mark it's just the title to the thread is Bi-amplification. Bi-amping (ie passive) can be beneficial but this is more when the amps aren't up to the speaker load. Active operation can be far more beneficial though the rest of the system has to be up to scratch too as it can be quite revealing. Of course a lot depends on the speaker involved. For years I've run speakers using a wideband driver covering 100Hz to 8kHz with the tweeter using a first order xover. The wideband driver does not have a crossover. I run bass actively via a digital xover with room correction DSP. This works well, the midrange has no xover is let's say "unencumbered", it sounds more directly connected to the amp. I have a second set of speakers with a similar bass arrangement but using an Alpair 12P fullrange driver 150Hz upwards. For these speakers I use a capacitor at the input of the amp to cut the bass from the amp and speaker- this is very benficial; it may be due the Alpair cone being small so it unloads the driver of much of the bass.

That's my next plan - to remake my OB's using 20mm acrylic and use a pair of Alpairs with the 15" Eminences.

[Clive]

That's my next plan - to remake my OB's using 20mm acrylic and use a pair of Alpairs with the 15" Eminences.

I saw that....should really nice looking. The 12Ps are amazing but need a horrible amount of time to give their best. They sound a little but not massively different to my Bastanis and I would say they are on a par in terms of overall sound quality. I wouldn't say the Alpairs sound like a cheaper driver that's almost as good.

[Haselsh1]

The title of this thread had me totally confused when I started to read the damn thing. I have now given up as I don't care for active anything. I use two power amps but for monoblock use.

[Ali Tait]

I saw that....should really nice looking. The 12Ps are amazing but need a horrible amount of time to give their best. They sound a little but not massively different to my Bastanis and I would say they are on a par in terms of overall sound quality. I wouldn't say the Alpairs sound like a cheaper driver that's almost as good.

Good to know Clive, that makes them a serious bargain..

[cloth-ears]

The title of this thread had me totally confused when I started to read the damn thing. I have now given up as I don't care for active anything. I use two power amps but for monoblock use.

I see your point Shaun. I should have called the thread:-

“Using two amplifiers with an active crossover could give you a better sound but please don’t read any further if you get confused easily or are totally against anything active and believe that monoblock amplifiers are better despite the lack of any scientific proof”

I’ll try harder next time :lol:

[mikmas]

The scope is endless and with a bit of experimentation you could end up with a truly outstanding sound for a tiny budget. Give it a try sometime....

I think I messed around with something similar a while back and intend to come back to it - the result was well worth considering but I have some questions being an absolute numpty when it comes to Xovers.

Basically I have a pair of Quad-Lite speakers I use on my desktop (for which they are ideal) These are amped by a Quad 33/303.
I dug up an old pair of B&W DM10 from the loft. One had a knackered tweeter so I removed both and their related filter network. I then wired the B&Ws to the 303 instead of the Quad-Lites. The QLs I wired to a Topping 2 amp fed from the Aux output of the 33. The result was great - the Lites have a very clear high frequency response which suits the poor bass delivery of the Topping 2 and the remaining B&W drivers deliver good bass grunt from the 303 without using the 33 tone controls. Overall frequency balance was powerful with no noticeable lack of mid range capability. I intend to rebox the B&Ws at some point (after clearing the garage to make some woodworking space ....)

My question really is whether removing the existing and remaining crossover filters from both sets of speakers would be a good idea and improve the sound further?

[Ali Tait]

The problem is, you need to know what frequencies the crossovers used so it can be replicated accurately.

[DarrenHW]

... I have a second set of speakers with a similar bass arrangement but using an Alpair 12P fullrange driver 150Hz upwards. For these speakers I use a capacitor at the input of the amp to cut the bass from the amp and speaker- this is very benficial; it may be due the Alpair cone being small so it unloads the driver of much of the bass.

I'm thinking of building a pair of OB's with the same arrangement, can I ask:
what "18" bass" (shown in your sig) you are using? (I've been advised the Goldwood GW-1858 driven by the iNuke would be a good pairing)
how have you implemented the capacitor at the input of the amp?
Thanks,

[Clive]

The problem is, you need to know what frequencies the crossovers used so it can be replicated accurately.
Very true and add in slopes & phase plus whether there's any padding resistors.

[Clive]

I'm thinking of building a pair of OB's with the same arrangement, can I ask:
what "18" bass" (shown in your sig) you are using? (I've been advised the Goldwood GW-1858 driven by the iNuke would be a good pairing)
how have you implemented the capacitor at the input of the amp?
Thanks,
I have a Goldwood, mine came from a friend so I'm not sure of the model and it's not on the driver. I use an iNuke too.

Re the amp capacitor at the moment I have an RCA plug and socket with the cap in series on the live side and of course the grounds link with a short length of wire. I can't recall the value....something like 0.15uF but this depends on the input impedance of the amp and then experiment a little.

[cloth-ears]

I think I messed around with something similar a while back and intend to come back to it - the result was well worth considering but I have some questions being an absolute numpty when it comes to Xovers.

Basically I have a pair of Quad-Lite speakers I use on my desktop (for which they are ideal) These are amped by a Quad 33/303.
I dug up an old pair of B&W DM10 from the loft. One had a knackered tweeter so I removed both and their related filter network. I then wired the B&Ws to the 303 instead of the Quad-Lites. The QLs I wired to a Topping 2 amp fed from the Aux output of the 33. The result was great - the Lites have a very clear high frequency response which suits the poor bass delivery of the Topping 2 and the remaining B&W drivers deliver good bass grunt from the 303 without using the 33 tone controls. Overall frequency balance was powerful with no noticeable lack of mid range capability. I intend to rebox the B&Ws at some point (after clearing the garage to make some woodworking space ....)

My question really is whether removing the existing and remaining crossover filters from both sets of speakers would be a good idea and improve the sound further?

Hi Mike, and thank you for your positive contribution. A quick look online should tell you the required crossover frequency of your speakers. The crossovers in the speakers should be completely removed or at the least bypassed. The active crossover has much lower distortion and when in place the amplifiers would be connected directly to the drive units. The chap selling the active crossovers will supply them with any crossover point you require at no extra cost. You will however need a second amplifier. The 303 should be sufficient to supply the grunt and a smaller amp could be used for the treble.

[Puffin]

The title of the thread says Bi-amplification. That means two amplifiers. I never mentioned the word "passive" in the title. It should be obvious to anyone reading that I’m advocating the use of “active“ crossovers.

Cant people just post a thread for something they think may be useful to others. Why do people get bogged down with semantics? I’m not writing a paper on it for Christ’s sake. Take from it what you will. If only one person finds it useful I’m happy

Hear Hear. I am a f*"king idiot and I knew exactly what you were talking about.

[cloth-ears]

Hear Hear. I am a f*"king idiot and I knew exactly what you were talking about.

Thank you Puffin, you made my day :cool:

[DarrenHW]

I have a Goldwood, mine came from a friend so I'm not sure of the model and it's not on the driver. I use an iNuke too.

Re the amp capacitor at the moment I have an RCA plug and socket with the cap in series on the live side and of course the grounds link with a short length of wire. I can't recall the value....something like 0.15uF but this depends on the input impedance of the amp and then experiment a little.

Excellent, thank you Clive.

[Arkless Electronics]

You can't just take a passive speaker, remove the crossover and use an off the shelf generic crossover to make good active speakers. Sure, they will work, but are unlikely to be accurate or natural sounding.... and if accurate and natural sounding aren't that important to you then just buy some PA speakers and get all the punch and dynamics you can handle on the cheap! 'Cos that's about what such home made active speakers are likely to sound like :eek:

[YNWaN]

Frankly Jez, I think you are wasting your breath.

Cloth - ears, you choose to believe whatever you want. The fact is that your post title and first sentence say one thing and the rest of your post describes something that is fundamentally different. I'm sorry if you don't understand the difference, but I can't be blamed for that.

[Clive]

Very true and add in slopes & phase plus whether there's any padding resistors.
I realise it's bad form to quote myself but.....I will anyway. The quote above was in the context of knowing the crossover frequency, I was making the point that there is a lot more to it. Playing with active with just crossover frequencies might be fun and interesting but it's unlikely to be great quality. Add to that the chances of blowing tweeters as there's nothing protecting them from switch on/off thumps....well just bear that in mind.

[mikmas]

Playing with active with just crossover frequencies might be fun and interesting but it's unlikely to be great quality. Add to that the chances of blowing tweeters as there's nothing protecting them from switch on/off thumps....well just bear that in mind.

What's a blown tweeter in the grand scale of things? In my case the speakers in question have been gathering damp in an attic for 8 years; they are crying out to see some real coil on coil action :lol:

Learning is about having fun and blasting out some mental cobwebs occasionally - to hell with theory ;) ......