Best way to bi amp my QLS-1's?

Just wondering what experince everyone has with the best setup for bi-amping a set of the QLS-1's. I just got my other amp so I have a pair of equal amps, SAE 2400L's. I also have a SAE 4000 active crossover, that is a two way crossover. Their are a few ways I could do this and I wondered of the people here which way they found to be the best way. I have one speaker now powered biamped but I need some more banana plugs to do the other driver. The way I have it set up now is vertically bi-amping them, using one amp to power one speaker channel A driving the Watkins bass driver and channel B driving the mids and hi's. I have it connected straight in the OEM connections in the back of the speaker so I am running it thru the passive crossover of the speaker. That is where I have a my concerns. Why am I using an Active Crossover and then just running it thru a passive one.

One other idea I had was to eliminate the Active Crossover and use each Amp as a mono amp by connecting the terminals into to positive terminals of the amp. That would make the output of my amp at probably 400 watts to drive the one speaker and let the active crossover do the sorting out of which speaker gets what frequecy.

Or I should I just eliminate the Active Crossover and send the full signal bandwidth to the speakers using one channel to power the bass and the other to power the mid-hi's and let the passive crossover do its job? I hope that I presented my questions well enough I have waited a quite a while to find a good clean amp so that I have a good pair and look forward to hopefully an even better sounding system.

Sure....I'll throw my Toonies worth at it. Now I don't have enough amps to bi-amp (just a bi-wire setup), but in theory, I don't see an active crossover being of any use here, and may just complicate things. By removing the tie wires from between the two sets of connectors (you've done this right?), the internal crossover is severed into two crossovers; one set for the Watkins, and another set for the mid-bass,mids and Emits. It's been all taken care of by Arnie and crew, so just feed each section the juice from the amps in horizontal or vertical configuration. The QLS's will work as designed.

I know there are some other theories on this re the active crossover, but I'll have to see some pretty convincing articles to sway me. The only way the active would be of use is if the internal crossover was totally ripped out and each driver section driven by separate amps. That would be an interesting project huh?

I suppose if one thought they could improve the transition between the woofer and midbass drivers, an active could be played with. But only if it was felt there was excessive overlap currently.

Hmmm, maybe that was a Tooney and a Looney worth ?

Looking forward to being re-educated.

Ken Boyd said:

One other idea I had was to eliminate the Active Crossover and use each Amp as a mono amp by connecting the terminals into to positive terminals of the amp. That would make the output of my amp at probably 400 watts to drive the one speaker and let the active crossover do the sorting out of which speaker gets what frequecy.

Click to expand...

I remember reading (I think :headscrat) that when you mono an amp, it's ability to handle low impedances is reduced. Hopefully someone can confirm or debunk this, but if so it's worth considering.

I vertically bi-amp mine using a pair of SAE P-250s, no active crossover.

Not sure using the 2400L as a mono amp is going to be the way to go. Firstly, I don't believe (may be wrong) you can bridge the 2400L, so there won't be any net power gain.

Secondly, as Kencat notes, bridging amps effectively halves the impedance handling capabilities of the amp (so an 8 Ohm speaker load looks like a 4 Ohm load to the amp). Given the relatively low impedances of the big Infinities, doing anything that reduces your amps' ability to handle low impedances is generally not recommended.

David

Ok update, I found another pair of leads with banana plugs have everything connected and operational. I have them bi-amped thru the active crossover, vertically I think they sound worse than when just powered with one amp with no crossover. and it seems like the amps are putting out more current for less db's. I did remove the jumper wire, I am running channel A of each amp to power the bass drivers and channel B is driving the mids-hi's. I think I will try next thing. I am going to just use each amp without the active crossover and use the same configuration only eliminate the active crossover and use just the passive one in the speakers. I would have thought that by using two amps I wouldn't have to turn my pre-amp up as much to get the same db output. It seems with the active crossover I have somehow lost a lot of efficency it thats possible. Not that I am lacking any ablity to get some serious db's but doubling the power I would have thought would have increased the output in db's. It use to be at one watt I was pretty loud.

I think I will try your first option, thanks! But I have to say many people claim these are hard to drive, I found that using just my one amp, they really sounded great and I could never even imagine listening to them at even half volume, it would have simply been to loud.

And thank you both on the advice on not bridging the amps, I would have hated to mess them up, I had a hard time finding a good second one for a reasonable amount, and only because another bidder didn't pay that I was able to get this one, looks like new and still in the orginal box.

I have tried biamping my Sigmas for a few months, vertically and horizontally with SS amps, and i couldn't tell any difference so one amp will go to sale. Now i heard good things about using tube amps on top so that's on my wish list for next year..

Ok vertically bi-amped using just the passive crossover, sounds like it did when I had it powered with one amp, maybe a little tighter bass and more presence and hi's. Actually I am a bit dissapointed, I thought that with it bi-amped I would notice a major difference. Maybe I expected to much considering they sounded great to me just as it was. I will give it some time like this, sometimes I find it takes a while for me to realize small improvements when something already is pretty good. But one thing I need some better splitters. The pre-amp has two outputs but the parametric EQ only has one so in-order to use the EQ I have to use two splitters to provide input for two amps, and I don't have any good splitters, just junk from Radio Shack, all my interconnects are pretty good pure silver with really good connectors, don't know how much that matters but seems silly to have good expensive interconnects only to have them running thru a pair of cheap splitters.

Ken,

give this a read - http://sound.westhost.com/bi-amp.htm#bi_wiring

It completely destroys what I said above (I'm ok with that). Requires horizontal bi-amping though. The way I read this is that by filtering the signal (active crossover) before the amps, the power requirement of each amp is reduced.

Why were you using the active crossover initially? You must have had a basis for doing so, and I am curious to what your reasoning is. I'm still sceptical a bit by some of the above authors arguments, but he most likely is more knowledgeable than me about this.

Your displeasure using the active crossover - could it be that some of the cables were crossed up? i.e. not hooked up correct? The vertical bi-amp would need some real noodling to get it all wired right. Just saying to make you think twice :scratch2:

The horizontal set-up seems to make a little more sense in that one amp is totally restricted to a certain frequency range.

Then, the million dollar question is - where and how is the active crossover set at the woofer to midbass transition, especially if dealing with old internal crossover components that may have things shifted a bit.

Getting late, continue later.

Hello
I have found that it is better to Bi Amp Horizontal.
The theory is that each amp can just amplify a certain frequency range.
Also If you have gain controls on the amp it allows for minor balancing.

So I would suggest this try The Horiz Bi Amp with out the Active Crossover.

The reason to use an Active Xover is to only pass the frequencies that the amp is going to be reproducing.
Since you are still using the passive Xover in the speakers it still will do its job and pass only the frequencies required to the lows and highs.

Regarding the Active Xover what do you have the Xover points set to?? What type of filter does it use? Do you have options of the filter type?

After you evaluate this setup try the active Xover in Horz Bi Amp you may find that it is a weak link and does more harm than good.

Now in regards to the volume question I have found that you will not end up with twice the volume
just does not happen what you should hear is a overall better sound due to the amps working less and having more headroom.

Hope this helps

i'm with goat here. depending on the relative level of the surrounding electronics, an active crossover can quickly become a weak link. however, i'm not sure it should sound bad or anything, so you might want to try again and be very careful with the wiring, as mentioned. and as has been hinted at, when you add in an active crossover set at the speakers' passive crossover point, you're actually creating a -6dB point, and the amplitudes will no longer add to be flat. the safe thing to do would be to have independingent high and low crossover points which are an octave below and above the original crossover point, respectively. personally, i'd just leave it in the passive vertical setup and be done with it.

Quite clear I have all the cables correctly routed, I have decades of experince installing sound systems, commercially working as a contractor for most of the large audio video providers across the country. My reason for bi-amping was that by using a active crossover you reduce the range of frequencies that the amp has to amplifly. A powered sub doesn't have to use near as large an ampliflier to reproduce generous bass because the amp is only having to amplifly a small spectrum of the audio range, that was what I was lead to beleive. I am not an audio engineer (wish), but I have installed many large systems and my experence with the systems that they design tend to make me beleive they do it for a reason. Many of the systems use active crossovers and they don't use any passive crossovers so I was using the active crossover to limit the amps requirements to only have to amplifly the frequencys needed and not the full range. That being said I knew that the active crossover was only going to be marginally useful for tailoring the sound because the passive crossovers and filters were going to limit my ablity to change any of the crossover points between the bass, midbase, midrange, and hi's

As to why I was attempting to vertically bi-amping them, because that is what is recommended by Infinity. Their claim is that by horizonally bi-amping their speakers that use the Watkins DVC driver you can litterally suck up all the reserve power of the power supply trying to amplify two Watkins DVC drivers on passages where their are large amounts of bass signals. Where as the mid-hi drivers don't require as much of a drain on the amps power supply, so rather than use one amp to power two Watkins drivers use one channel of an amp to provide bass to one speaker and one channel for the mid hi drivers. Normally I have never bi-amped vertically, most the systems I have installed are 70 volt systems and I use large amps to power all the subs and others to power the mids and hi's. I think that in most cases you would bi-amp that way as in the case of the RS-1b's and all of the other large Infinity systems that don't use a Watkins driver.

For the most part I am going to just keep the set up I have now bi-amping them vertically without the active crossover, and keep my eyes open for a larger amp. Its not like I was not really happy with the system the way it sounded before I bi-amped them, to me they sounded great. And I just liked the rack full of all the different componets that I had. But everyone kept saying that the only way to really make the QLS sound good is you have to bi-amp them so I took them for their word and expected possibly more that I should have.
.

goat67 said:

I have found that you will not end up with twice the volume
just does not happen what you should hear is a overall better sound due to the amps working less and having more headroom.

Click to expand...

IIRC, isn't it true that doubling the power only increases output by 3db? That would explain why you aren't hearing a difference in volume by bi-amping. I agree that you will improve the sound by adding headroom, as well as protecting your emits from excessive heating due to clipping. Again if IIRC, you'll need 10 times the power to double the volume.

Kencat said:

Ken,

give this a read - http://sound.westhost.com/bi-amp.htm#bi_wiring

It completely destroys what I said above (I'm ok with that). Requires horizontal bi-amping though. The way I read this is that by filtering the signal (active crossover) before the amps, the power requirement of each amp is reduced.

Why were you using the active crossover initially? You must have had a basis for doing so, and I am curious to what your reasoning is. I'm still sceptical a bit by some of the above authors arguments, but he most likely is more knowledgeable than me about this.

Your displeasure using the active crossover - could it be that some of the cables were crossed up? i.e. not hooked up correct? The vertical bi-amp would need some real noodling to get it all wired right. Just saying to make you think twice :scratch2:

The horizontal set-up seems to make a little more sense in that one amp is totally restricted to a certain frequency range.

Then, the million dollar question is - where and how is the active crossover set at the woofer to midbass transition, especially if dealing with old internal crossover components that may have things shifted a bit.

Getting late, continue later.

Click to expand...

Good info, but as to requireing it to be horizontally bi-amped I saw nothing which stated that. In fact I don't think the speaker knows the difference what channel of what amp your using. You could use four mono amps or one four channel amp and that would not matter. The channels should not be effected by what the other channel is doing so no matter what method you use horizontal or vertical should matter, except for what infinity was concerned about and that was to much of a demand on an amp that has only one power supply. If I had amps that each channel had its own powersupply, (some do) it wouldn't matter. And to be honest I doubt that I will ever be pushing these speakers at a level that draining the powersupply on these amps will take place I just did it because to me it really didn't make a difference. I looked at four channels of power and if Infinity didn't suggest using two channels from the same amp then so be it. I did have a little concerns about two amps being of equal power and that the left channel might be slightly louder or quieter that the other channel but that really didn't make that much of a problem as I could simply adjust the line attenuator on my EQ.

But I scrolled up on that article you linked to and right at the first it states what I already had come to a conclusion, that in order to bi-amp using an active crossover you must first eliminate the passive one.

goat67 said:

Hello
I have found that it is better to Bi Amp Horizontal.
The theory is that each amp can just amplify a certain frequency range.
Also If you have gain controls on the amp it allows for minor balancing.

So I would suggest this try The Horiz Bi Amp with out the Active Crossover.

The reason to use an Active Xover is to only pass the frequencies that the amp is going to be reproducing.
Since you are still using the passive Xover in the speakers it still will do its job and pass only the frequencies required to the lows and highs.

Regarding the Active Xover what do you have the Xover points set to?? What type of filter does it use? Do you have options of the filter type?

After you evaluate this setup try the active Xover in Horz Bi Amp you may find that it is a weak link and does more harm than good.

Now in regards to the volume question I have found that you will not end up with twice the volume
just does not happen what you should hear is a overall better sound due to the amps working less and having more headroom.

Hope this helps

Click to expand...

Pretty much just what I have found, not twice the volume, overall a slight better sound, although I seems to me the power indicators don't show it working any less, but for now I see no real advantage to change over to horizontal. Are not each channel of the amps doing the same thing either way vertical or horizontal, because by not using the active crossover I am amplifying the full range of audio on all four channels. If I choose to use the active crossover in the future I will go in and disconnect the passive one.

Good write-up there Ken.

There is a limit to everything - law of diminishing returns and all that.

Maybe you are there now(limit) or too close, to hear any differences. I suppose the only way to know which set-up was best would be to take the speakers to clipping with the same test song or laboratory instrument in each set-up and measuring SPL at that point. But that is potentially destructive testing :tears:

Your experimentation has been interesting though and the results will be useful to others.

Could be different results though if someone only had 100W x 100W amps instead of the 200W x 200W iron you have.

Agree....for now just enjoy the tunes.

Thanks, thats just what I was doing, listening and enjoying them, and thank you all for all the great info as usual. Just reading all the post on this site in the last few months I can only imagine the great sound that some of the people here must get from their systems, based on the level of educated and informative info that they all have, not to mention all the really nice gear they all own.

i didn't try all that many amps on my QLS1's, but i can tell you they sounded a lot better with a single beastly 500wpc amp than two 250wpc amps in a passive horizontal biamp setup. how much of that was due to sheer amp quality (the PC5002M versus the DH-500 and M-80) i don't know. a good test would be two PC5002Ms, but i didn't have enough working channels when i had multiples of that guy.

My leanings as well, in fact I will find out in a few days, there are a bunch of big amps just pulled from a place, all Crowns some 800's and some 1600 watts. They are not the Reference models but they are pretty good and will do to find out what some major current will do. I have a pair driving my pair of RS-1b's and they sound really good. I should have purchased that pair of Classe 700 mono blocks off the other site, I think that pair would have been perfect for the QLS-1's

Horizontal with the xover

I have experimented a lot with my speakers( k9's ) I found what worked the best for me was a horizontal bi amp using a xover ahead of the amps to divide the signal coming out of the preamp. Without the xover the amps are reproducing the full signal so there was not much of any gain. When using the xover ahead of the amps one amp does the low part of the signal and the other only does the high part. There was better sound from this method at least for me the amps are only reproducing either the high or lows and not all. they ran much easier and I had a little gain in headroom as well as a better quality of sound.