Bi amping speakers

Bi-Amp Bi-Wire information
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bob p
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Post by bob p » Mon Sep 17, 2007 1:01 pm

Bigred wrote:Ahh this thread brings back memories. Its strange how many speaker manufacturers call their speakers bi-ampable but all they do is seperate the passive crossover network into HF & LF... no bypassing :-k This I have been told by experts is "fools" bi-amping and ultimately your not bi-amping unless filtering at the line level... in the truest sense I would agree BUT lets just call the fools way passive bi-amping.
there was a lot of misinformation about bi-wiring and bi-amping in the lay press back in the 1980s when speaker manufacturers used to provide "ready to biamp" speakers. unfortunately, 20 years later it seems that as many people remain confused by this as ever.

More precisely, "fool's biamping" refers to the practice of amplifying full-range signals in two amps, and then throwing away part of the amplified signal by causing a dead short to ground in the output of the amplifier at frequencies that are above or below the crossover point. the dead short is caused when the user mistakenly disconnects the physical connection between the HF and LF sections of the passive crossover without also segregating the HF and LF sections of the signals going into the amp using an active crossover. I think that everyone would agree that presending a dead short to your amp at all frequencies (by shoriting your speaker cables together) is a bad idea, and that presenting a dead short at selective frequencies (by using only half of a a passive crossover on a full range signal) is a bad idea as well.

To dispense with "fool's biamping," all that is required is to separate the HF and LF content prior to amplification using an active crossover. That will remove the "dead short" problem when the two segments of the passive crossover are unlinked. Doing that will place a lot less strain on your amps.

Just to clear things up then, its simple enough to perform "true biamping" instead of "fool's biamping" -- all that is required is an active crossover prior to amplification. Retention of the passive crossover circuits in the speakers has NOTHING whatsoever to do with this.
Carver Preamps: C-1, C-2, BillD's JVD-modded C-4000, C-9
Carver Amplifiers: BillD's C-500, M-1.5t (4) PM-1.5 (4) M-500t (2)
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bob p
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Post by bob p » Mon Sep 17, 2007 1:04 pm

Total elimination of the passive crossovers while actively bi-amping is something that is available as an option for people who want to take their bi-amped systems one step further. By removing unnecessary high voltage components from the signal path between the amp and speaker, another potential source for distortion is eliminated.

The step of eliminating the passive crossovers in the speaker boxes isn't something that everyone will want to do. There are some speakers, such as 3-way 4-way, 5-way designs, that can't have the internal crossovers removed when biamping. For those speakers, retention of the internal crossovers is needed unless you're willing to tri-amp, quad-amp, or pent-amp your system.

There's also a case where some speakers will have crossovers that are complicated designs -- designs that include hipass fitlers, lowpass filters, and notch filters. Its its easy enough to use an active crossover to replace the frequency separating responsibilities of the passive crossover. What is more difficult, though, is to determine whether other responsibilities are being performed in the crossover as well.

some crossovers will incorporate a notch filter that is designed to eliminate resonant peaks in a speaker's response. By totally eliminating this sort of device, it becomes the user's responsibility to perform adequate pre-amplification filtration to compensate for ALL of the passive crossover components that are removed. There are previous posts in this thread (and in the AL-III threads) about parametric EQ that should also be read.

the long and short of it is that its easy enough to provide active bi-amping using an active crossover and two amps. To go one step further, and eliminate the crossovers in your speakers might provide additional benefits, but anyone who attempts this had better be damned sure that they know what they are doing. If you do thing wrong, taking this final step could make things worse instead of better; its not something that everyone would want to do.

Finally, there aare some speakers that just aren't suitable candidates for biamping, because they provide unique forms of filtering that go beyond traditional frequency separation. In cases like this, your best bet is probably to rebuild your crossovers using better components. Other people here have lots of experience if you're interested in going down that route.
Carver Preamps: C-1, C-2, BillD's JVD-modded C-4000, C-9
Carver Amplifiers: BillD's C-500, M-1.5t (4) PM-1.5 (4) M-500t (2)
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Post by dartman » Mon Sep 17, 2007 1:16 pm

@bob p,

please correct me if I'm wrong. I have to make active crossover to properly bi-amp my Infinity Renaissance 90.

Connecting just two amps for hi and low using existing passive crossover is waist of money.

Sorry if it's stupid question but I'm not technician.

cheers
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bob p
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Post by bob p » Mon Sep 17, 2007 1:39 pm

my opinion on this is that if you don't use active crossovers, you're wasting your time and money.

if you haven't done so already, start reading this thread from the beginning. the answers to your technical questions have probably been answered already. there is a lot of good reference material starting on Page 3.

i hope this helps.
Carver Preamps: C-1, C-2, BillD's JVD-modded C-4000, C-9
Carver Amplifiers: BillD's C-500, M-1.5t (4) PM-1.5 (4) M-500t (2)
Repair/Restoration/Upgrade expert for all of these components.

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Post by dartman » Mon Sep 17, 2007 2:08 pm

Thanks,

this is very useful and helpful.
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faustus
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Fear No Signal

Post by faustus » Sat Oct 20, 2007 4:46 pm

Update concerning biamplification using the M-400t...

Earlier in this thread, there was conjecture that an M-400t might have problems if it were used to drive anything less than a full-spectrum audio signal. Since I now have two M-400t units and want to setup a biamped rig with them, I called Rolland Barr at Hi-Tech Audio, Ltd. to get his take on the subject...

Rolland opined that the M-400t and other "t-modded" models are not considered "early" Carver designs and should have no problems driving any clean audio source, be it full spectrum, low freqs only, or high freqs only.

When I asked about the possibility of rail switching logic errors leading to a fried amp, particularly if driven with a high freq only signal coming from an external crossover, he said that he had not heard of such a thing.

Here's the best part...
When I told Rolland that I intended to setup a biamped rig with one M-400t to drive the low freq signals and one M-400t to drive the mids and highs, he told me to go for it AND that if either of the M-400t units developed any sort of problems, he would fix them for free, no questions asked. Wow, that's an ironclad guarantee to backup his "fear no signal" advice.

Rolland's word is good enough for me! I've got the M-400t's in place, the Ashly xr1001 crossover in place, AND IT SOUNDS GREAT! The lows are solid, the mids and highs are sweet, and the overall sound is more sorted out (into individual instruments and vocals, with a lower level of background "stuff") and more effortlessly delivered. For my system, biamping with an external crossover definitely improves the sonic quality.

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Post by Mr. M-500t » Sat Oct 20, 2007 4:59 pm

Man faustus, now you've really givin me wood :-
I just picked up a Rane AC-22 this morning.
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... :IT&ih=014
I plan on doing the same thing with my M-500t's and AL-III's \:D/ \:D/ \:D/

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Post by faustus » Sat Oct 20, 2007 6:49 pm

Mr. M-500t,

Go biamped and don't look back!

One of the coolest aspects of my newly biamped rig is that I can now spend time watching TWICE AS MANY power level LEDs bouncing around -- in your case, it would be power level meters, but still captivating, yes?

With the AL-III, when you make the jump to biamp, are you merely separating the low and high sections of the crossover -- meaning that you keep the internal passive crossover's filtering on each of the low and high legs?

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Post by TNRabbit » Sat Oct 20, 2007 7:03 pm

FYI:

BiWIRING vs BiAMPING:


Biwiring is running separate amps to the hi/low through the original crossover. There is SOME good to doing this. It allows you to use lower power amps to reach the high power requirements of Carver speakers. By effectively doubling your power with two amps, you are realizing more headroom.

Bob Carver himself recommended biwiriing Amazings in Sunfire manuals, using the current source to drive the ribbons & voltage source to drive the woofers (I have personally found this to make a big difference in the clarity of the bass).

Although biamping is better because you do away with any in-line interference from the internal crossovers & release each hi/low amp to do it's job in only that particular frequency, much good can be realized from biwiring.
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From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.

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Post by Mr. M-500t » Sat Oct 20, 2007 7:15 pm

faustus wrote:Mr. M-500t,

Go biamped and don't look back!

One of the coolest aspects of my newly biamped rig is that I can now spend time watching TWICE AS MANY power level LEDs bouncing around -- in your case, it would be power level meters, but still captivating, yes?

With the AL-III, when you make the jump to biamp, are you merely separating the low and high sections of the crossover -- meaning that you keep the internal passive crossover's filtering on each of the low and high legs?
I am bi-amped through my Velodyne Sub right now !
When my Rane gets here I'll be Bi-passing the AL-III Cross Overs.

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Post by faustus » Sat Oct 20, 2007 7:40 pm

If you bypass, as opposed to separating the legs of, your internal crossover, don't you have the "6kHz notch" to deal with, or is that only an issue with the Silvers and Platinums?

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Post by Toy Maker » Sat Oct 20, 2007 7:44 pm

It's funny, in the Car Audio world, Bi-Tri-amping is the standard. I don't understand why, in the home audio world, it's such an odd thing.

I also don't understand why an active crossover for the home is $1000 avg.
You can buy 3-4-5-6 channel Car audio crossovers for $100-200 anywhere. I would expect the internal electronics to be pretty close in parts. Why the HUGE price increase... Just cause they know you guys will pay it ??

Soundsream was/is one of the HIGH END car audio manufacturers, probably close to having Sunfire in your car. They have always had HUGE amps, and crossovers.
Everyone can laugh if you want, but a car crossover WILL run very well in your home system, for a fraction of the price. If you want to spend $1000 to split your frequencies 2 ways, feel free, I know the "tweekers" will.

For anyone wanting to say the obvious... ( Yeah, but it's car equipment it's 12V ) duuuu... here's the fix for $20 or less.
http://www.radioshack.com/product/index ... age=search

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Post by TNRabbit » Sat Oct 20, 2007 7:47 pm

faustus wrote:If you bypass, as opposed to separating the legs of, your internal crossover, don't you have the "6kHz notch" to deal with, or is that only an issue with the Silvers and Platinums?
Yes, you do. There's a couple of other dips/spikes to deal with, too. It appears most folks that truly bi-amp have chosen to ignore these.
TNRabbit
Image

From FrankieD's lips to your ears: Sunfire - a quiet box of endless power.

Sunfire TG-IV/400~7 Amp
Carver SD/A-360 CDP
Benchmark DAC-1
Sony SACD/DVD-A
Active bi-amp: Ashly XR-1001 & 2 Rane PEQ-15s
Main: HotRodded AL-IIIs
Sub: Klipsch RT-12d
Center: Sunfire CRS-3c
Surround: Sunfire CRS-3 (x 2)

OconeeOrange wrote:"Gary likes to play it 'loud' as do I. His system begs you turn it up until you die"

RIP WIlliam B. Dibble, 1948-2012. I'll miss you my friend.

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Post by Mr. M-500t » Sat Oct 20, 2007 7:54 pm

faustus wrote:If you bypass, as opposed to separating the legs of, your internal crossover, don't you have the "6kHz notch" to deal with, or is that only an issue with the Silvers and Platinums?
I don't think it will be a problem because the AL-III already have their own set of High Frequency, Upper Mid and Woofer "Q" Controls on them. We shall see. I made a friend here in Portland that did the same thing with his Carver speakers and he can't get enough of them. I just spoke with him again today. We're getting together next week-end. I think he has the Plat's.

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Post by Toy Maker » Sat Oct 20, 2007 7:56 pm

Go straignt biamp 1st... listen to it, and see what you think before messing with the frequency curve... that's my penny and a halfs worth.

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