Bi-amping using my NAD T773...awesome!!

[pearsall001]

As many of you know, I recently sold off some of my gear. One item in particular was the Van Alstine OmegaStar 440EX amp (220x2). I was concerned that my AAD 2001 monitors (86db sensitivity/8ohm) would suffer the consequence. Man oh man was I ever wrong. As good as the AVA amp was both musically & power wise, my NAD T773 came thru without skipping a beat. Being a 7.1 avr & only running a 5.1 system I decided to see if I could bi-amp using the spare amp. I emailed NAD & they told me how to do it, very simple to say the least. WOW!!! not only am I impressed with the sweet, laid back sound of the NAD, the power is just awesome. Truth be told I don't miss the AVA amp at all. That's not putting down the AVA at all, I'm really giving kudos to NAD for a tremendous product that I had sitting there all the time.

I read a lot here about the necessity of a 2 channel amp to really make your speakers sing. I guess it all depends on the quality of the AVR you have & if you can bi-amp with it. I would highly recommend going the bi-amping route first before investing in a separate amp. Just a thought.

[Yashu]

I have owned my NAD integrated for longer than any of my other parts, I have thought about a lot of different amps, but when push comes to shove, I cannot find a GOOD reason for me to switch without having to spend ALOT more money.

The power is truly amazing really... rated at only 60 watts, this thing feels like an amp of several times that power. NAD has done a pretty damn good job at giving you quality without wasting needless money and space on pointless features. The sound is something that I cannot find much fault with. I have listened to many other amps, and again, I come back to the NAD with renewed appreciation. The sound is full, but not too forward, laid back... like you said, but not without dynamics or detail. NAD has a "house" sound that people either love or hate.

I will probably upgrade to a seperate pre eventually (the fact that everything is moduler in a NAD integrated/receiver is great in itself), but the NAD poweramp section is good enough that I don't see needing to replace it any time soon.

That is really cool that you are using the extra channels in your reciever to bi-amp... I never thought about that, but what a great way to double the power for your mains when you have a multichannel reciever. I am glad to see another NAD fan... I feel like their prices puts them "below the radar" of alot of audiophiles.

[JimBRICK]

Nad Rules

[hearingimpared]

I need to get my ears on this Phil, I have a T773.

[heiney9]

That is really cool that you are using the extra channels in your reciever to bi-amp... I never thought about that, but what a great way to double the power for your mains when you have a multichannel reciever. I am glad to see another NAD fan... I feel like their prices puts them "below the radar" of alot of audiophiles.

Glad this has worked out. Just remember you are not really doubling the power. The extra channels still use the same power supply to draw it's power from and in some instances (not this one) bi-amping with extra channels results in no improvement.

H9

[madmax]

I read a lot here about the necessity of a 2 channel amp to really make your speakers sing. I guess it all depends on the quality of the AVR you have & if you can bi-amp with it.

Its certainly more about quality of parts and design than packaging decisions.

BTW, what TT/cart are you using for the source? :p

madmax

[pearsall001]

Yo madmax,

It's a toss up between the Clearaudio Statement TT & the Gemini TT. Damn, tough decision here. Little help please!!!! :D

Phil

[pearsall001]

I need to get my ears on this Phil, I have a T773.

Joe, you're gonna be listening in utter amazement. It sounds like you're sitting at the "Jazz at the Pawnshop" Nice I tell ya!!! Nice!! This NAD bi-amped is nothing short of amazing.

How do you like my new signature?

[dkg999]

But it's not 200 wpc, how can this be :o

[heiney9]

But it's not 200 wpc, how can this be :o

Oh man when Cathy see's this she's going to be all over you dkg999. I'll be checking back often :p .

[dkg999]

The lines about 10 deep to kick my ass, she'll have to take a number :eek:

[heiney9]

The lines about 10 deep to kick my ass, she'll have to take a number :eek:

I have a special "move to the front of the line" pass I could give to her :eek: <jk>. Ladies first!

[dkg999]

You could make a lot of money right now with that pass!

[pearsall001]

But it's not 200 wpc, how can this be :o

How does that work? How do I know what's being delivered between the 2 amps? The manual states: 7x110 in surround mode all channels driven, 2x145 into 8ohms,two channels driven. If I'm bi-amping do I multiply the 145 figure? That seems kind of high doesn't it. Anyway NAD is very conservative with their ratings. All I know is it gets the job done without breaking a sweat. I'll email NAD & get their take on this question. I'm more curious now.

[dkg999]

Ummmm, I think you missed the joke and sarcasm in my post!

[WilliamM2]

How does that work? How do I know what's being delivered between the 2 amps?

For one, you would have to know the resistance of each circuit in the crossover. The other thing to consider, is that even if the woofer section is drawing 100 watts, the tweeter section will probably only draw 5 to 10 watts to play at the same level. So even if you bi-amp, you are not doubling the power, or anywhere close.

[pearsall001]

Ummmm, I think you missed the joke and sarcasm in my post!

Not at all, you hit the nail right on the head ;) I know Cathy is phanatical about running at least 200 watts or go home!! I'm anxious for her response on this one. Who knows, maybe with bi-amping maybe I'm pushing more than 200? Anyone know how to figure this out?

[John K.]

Pearsall, no figuring is necessary; the same power supply section in your T773 is simply feeding its same amount of power through two sets of output transistors rather than one. The output transistors are simply valves which measure out the required amounts of power from the power supply section at given instants, but they have no power of their own to add. The available power to each section of your speakers remains the same as before; it isn't doubled and can't be increased by any amount. Your T773 was, and still is excellent.

[Yashu]

You are missing the point. You are assuming that the PSU is the only limit here, and that is just not true. Those transistors are most of that limit... the NAD specs prove this point very clearly: "7x110 in surround mode all channels driven, 2x145 into 8ohms, two channels driven."

This spec here clearly means that each channel stage transitors' limit is about 145 watts continuous, and that the PSU is strong enough to drive 7 of them at 110 watts. The OP was already driving 5 channels, so using the extra 2 would nearly be doubling the max *available* power to the set of speakers he is wanting to bi-amp. The fact that the HF sections of the speakers use less power just means that, on top of gaining the use of those dormant transistors, he is better distributing the load of his speakers.

Furthermore, with respect to NAD power supplies, all current NAD amps feature PE circuits, so there is reserve power for many times the rated wattage for short bursts of up to about a second or two, which is the reason NAD amps always sound more dynamic than their ratings suggest.

NAD designed this amp with driving all 7 channels in mind, why shouldn't it sound best this way?

[heiney9]

Believe what you want your explanation is pretty far off. Pearsal, glad you are digging it. Nothing wrong with NAD gear, enjoy. Isn't this hobby fun!

H9

[dorokusai]

Pearsall, no figuring is necessary; the same power supply section in your T773 is simply feeding its same amount of power through two sets of output transistors rather than one. The output transistors are simply valves which measure out the required amounts of power from the power supply section at given instants, but they have no power of their own to add. The available power to each section of your speakers remains the same as before; it isn't doubled and can't be increased by any amount. Your T773 was, and still is excellent.

I agree, you're simply getting what you had in the first place. It's more of a perceived change. If you hear a difference, then it exists, period. The amplifier was the same then as it was now, so it has little to do with actual power, because nothing really changed internally. That's why I love loudspeakers. They usually voice the changes, not the gear. We can speculate about load, source impedance mismatch and this or that but that's for a magazine.

I love the NAD PE and the cousin, Onkyo WRAT, in regards to amplifier design. Enjoy your gear, don't sweat the small stuff.

[Yashu]

But there IS a change, a real one... he is using 2 extra channel's worth of power transistors that were lying dormant before... and not only that, but he is now using a total of 4 channel's worth of power transistors for his mains instead of two. Two channels can deliver a total of 145WPC (since he was using 5, this value would have been lower), this is the max load for the transistors at 8ohms, but even if you use the rating at 7 channels continuous, he has access to 220 wpc now FOR HIS MAINS... The difference is enough to hear,the capability is there and the loads are more evenly distributed within the amp.

There is no reason to just let extra channels sit idle if you can do this... There is more to an amp than just a power supply... Why do you think that with two channel driven the amp can only deliver 145wpc (making it 290w total) but 110wpc over 7 channels (770w total)? He is hearing a difference because there IS one.

[heiney9]

But there IS a change, a real one... he is using 2 extra channel's worth of power transistors that were lying dormant before... and not only that, but he is now using a total of 4 channel's worth of power transistors for his mains instead of two. Two channels can deliver a total of 145WPC (since he was using 5, this value would have been lower), this is the max load for the transistors at 8ohms, but even if you use the rating at 7 channels continuous, he has access to 220 wpc now FOR HIS MAINS... The difference is enough to hear,the capability is there and the loads are more evenly distributed within the amp.

There is no reason to just let extra channels sit idle if you can do this... There is more to an amp than just a power supply... Why do you think that with two channel driven the amp can only deliver 145wpc (making it 290w total) but 110wpc over 7 channels (770w total)? He is hearing a difference because there IS one.

That's not at all how it works. Get your Google on and learn about amplification, outputs, multi-channel, power supplys, rail voltage, etc and then you'll understand. This no small subject so expect to spend a few weeks or more to grasp the proper concepts. It's not as simple as summing the manufacturer's specs. As a matter of fact that has nothing to do with it whatsoever.

Not trying to turn this thread ugly. I think it's great that Phil (Pearsal) is enjoying his receiver and it's new role in his rig, that's really all that matters.

H9

[hearingimpared]

Joe, you're gonna be listening in utter amazement. It sounds like you're sitting at the "Jazz at the Pawnshop" Nice I tell ya!!! Nice!! This NAD bi-amped is nothing short of amazing.

How do you like my new signature?

I can't wait to hear it. . . Nothing like trimming the fat.

[hearingimpared]

I think it's great that Phil (Pearsal) is enjoying his receiver and it's new role in his rig, that's really all that matters.

H9

This where I totally agree when these kind of debates go on. Phil hears something wonderful. . . He states it clearly, it doesn't matter whether it's amplification, front end, cables, wires or room treatments, he clearly hears and enjoys the difference because he has done so with his 773 now I want to try it with mine. I would have never thought to do so had Phil not tried.:)

[marker]

The extra channels still use the same power supply to draw it's power from ...

FWIW, the T773 has not just one, but two toroidal transformers, one for the front three channels, and a second for the other four. ;)

[madmax]

Those transistors are most of that limit... the NAD specs prove this point very clearly: "7x110 in surround mode all channels driven, 2x145 into 8ohms, two channels driven."

This spec here clearly means that each channel stage transitors' limit is about 145 watts continuous, and that the PSU is strong enough to drive 7 of them at 110 watts.

Totally agree here. Couldn't read the rest of it as I was falling asleep. :)

madmax

[cfrizz]

Enjoy Phil.:) H9 I do like a man who knows how to be a gentleman!:D

As for the rest of you...:p

[WilliamM2]

Everyone seems to ignore that the tweeter will only draw a few watts. I've done the experiment myself with my CSi40, I am currently bi-amping it with 2 channels of a 150wpc amp. It has no more output, or at least not enough to register on the SPL meter, than it did with one channel at 150wpc. Oddly enough, it still seems to sound the same as well.

[Yashu]

It depends from amp to amp... plus, there is a very good chance that if your amp was already of high enough quality, it was already able to deliver the power your speakers needed for their best performance.

NAD is very honest with their specs, as testing has consistently shown in measurements done by Stereophile and other magazines... They even measured their PE circuits and soft clipping... all pretty interesting actually. It is one of the reasons I respect NAD so much.

Anyway, I understand enough to know that there is more to an amp than a PSU... I never claimed to be an electrical engineer, I have only done some light electronics work and modding, but I don't think I am going to be convinced that output transistors have limitless power handling and that the only thing that matters is the power supply... sorry h9.

Don't get me wrong, there are plenty of cheap receivers out there with grossly overstated specs with puny PSUs, but NAD is not one of those brands.

I would have thought one would argue that an extra 75wpc would not yeald very much in terms of actual possible DB level before trying to argue about transistors and PSUs, that is what people usually argue about when it comes to this kind of thing.

I think that even if it would give you only a few extra max DBs, that max DB level doen't matter that much anyway, and that it is dynamics, power though transients, and a more evenly distributed load within the amp itself that would make this kind of project worth it.

I have OCD, and so even the fact that there are now no more dormant channels would make it worth it... to me anyway... since 7 channels were paid for, 7 should be used.

[Vr3MxStyler2k3]

Technically you arnt biamping, you are just powering to like signals into two jacks.

True biamping would have an amp crossed over to only runs the highs, and the other amp cut off from powering the highs -- so its doing all it can for each individual piece.

But anyway, cool deal.

[hearingimpared]

Ah ha . . . I don't think we could call it bi-wiring either. . . so did Phil come up with something new?

[Vr3MxStyler2k3]

And to comment on the other poster....

The tweeter may only use a few watts, because the crossover crosses over the signal.

However, the amp is actually powering a 20 - 20hz signal until it reaches that crossover, then it is broken down. But the power is still working just as hard as before - even if it is just a tweeter.

Thats what it comes down to with the crossing of the amps part...

[WilliamM2]

The tweeter may only use a few watts, because the crossover crosses over the signal.

However, the amp is actually powering a 20 - 20hz signal until it reaches that crossover, then it is broken down. But the power is still working just as hard as before - even if it is just a tweeter.


Actually, the amp is still powering 20 to 20K, but it is not working as hard. The woofer section on the CSi40 is 4.5ohms, the tweeter section is 400Kohms. Don't know the actual measurements of his speaks, but they will also have much higher readings on the tweeter circuit compared to the woofer circuit. How much power do you think the amp puts out into a 400Kohm load? Very little.

[pearsall001]

Maybe I'm missing something here. If the T773 can run all 7 channels at 110watts, & in stereo mode (2 channel...run 145watts) then if I'm taking the extra unused amp or unused power (surround back speakers) & bi-amping it with the power going to the fronts, how does that not increase the power going to my mains? I have speaker cables from the front channel going to the mid/woofer & speaker cables fron the surround back channel going to the tweeters. Running in stereo doesn't that make it 145watts to the tweeters & 145watts going to the mid/woofer? It seems logical, but then again what the hell do I know. It really doesn't matter how much the tweets & mid/woofer actually use (normal speaker usage is 10-12watts I believe) it's just that the reserve power is there when needed. I did email NAD & I'm waiting for a reply. Interesting topic for me, thanks for all the technical info.

[Vr3MxStyler2k3]

I have never in my life seen a 400k ohm tweeter?

Every tweeter I've ever had in my speakers have been the normal 4 or 8 ohm load by themself? And draw upwards of 50-100 watts continuous.

An amp will power a 20-20 hz signal regardless... it dosnt know what it is powering unless you tell it otherwise, which has to be done before the amp receives its signal. Not afterwards.

If you send a 120 watt signal of 20-20hz, to my understanding, its always going to be a 120 watt signal of 20-20hz... that is until you put something like a crossover before the amp receives the signal...

[Bill Ayotte]

Maybe I'm missing something here. If the T773 can run all 7 channels at 110watts, & in stereo mode (2 channel...run 145watts) then if I'm taking the extra unused amp or unused power (surround back speakers) & bi-amping it with the power going to the fronts, how does that not increase the power going to my mains? I have speaker cables from the front channel going to the mid/woofer & speaker cables fron the surround back channel going to the tweeters. Running in stereo doesn't that make it 145watts to the tweeters & 145watts going to the mid/woofer? It seems logical, but then again what the hell do I know. It really doesn't matter how much the tweets & mid/woofer actually use (normal speaker usage is 10-12watts I believe) it's just that the reserve power is there when needed. I did email NAD & I'm waiting for a reply. Interesting topic for me, thanks for all the technical info.

I think you are putting 220 to each speaker....110 on highs, and 110 on mid/lows....Technically, those channels are still driving something, so the 145 rule would not apply....Just my thought......

[Midnite Mick]

Phil, Phil, Phil....look at the trouble you cause with your shenanigans. :)

You should have just stated that "good, Nad, sound" and none of this would have started.

Mike

[hearingimpared]

Mike this stuff starts if someone mentions vanilla ice cream!!!!

[Midnite Mick]

I don't know if it is my imagination, but this stuff seems to be getting worse around here lately.

[WilliamM2]

I have never in my life seen a 400k ohm tweeter?

Neither have I. I am talking about the entire tweeter network, including crossover. Do you have any speakers on hand with Bi terminals? If so, remove any jumpers, and measure each set of terminals. This does not give you a true reading, but it will demonstrate what I am talking about.

If you send a 120 watt signal of 20-20hz, to my understanding, its always going to be a 120 watt signal of 20-20hz... that is until you put something like a crossover before the amp receives the signal...

But your not sending 120 watts, due to the higher impedence. The higher the impedence, the less power the amp will put out.

[heiney9]

Mike this stuff starts if someone mentions vanilla ice cream!!!!

Vanilla ice cream tastes like chocolate.

[pearsall001]

Phil, Phil, Phil....look at the trouble you cause with your shenanigans. :)

You should have just stated that "good, Nad, sound" and none of this would have started.

Mike

I had to liven things up around here, it was getting too boring!!! :D Anyway, I'm still looking for the magic answer. I don't think anyone's put their finger on the answer yet, just a lot of theory & speculation. Any thoughts??

[GV#27]

Technically you arnt biamping, you are just powering to like signals into two jacks.well its called passive biamping because the passive crossovers are still used.What he is gaining is some extra headroom.

True biamping would have an amp crossed over to only runs the highs, and the other amp cut off from powering the highs -- so its doing all it can for each individual piece.
"True"biamping using an active crossover that divides the signal before the amps has many more benifits than the passive version.

[Midnite Mick]

I had to liven things up around here, it was getting too boring!!! :D Anyway, I'm still looking for the magic answer. I don't think anyone's put their finger on the answer yet, just a lot of theory & speculation. Any thoughts??

Nah, I am not smart enough for all this. Try it without the fancy bi-output and then with it. Listen to some very dynamic music at a high volume and let your ears decide. I just know if I like what I hear or I don't...I am simple folk I guess:)

I personally think that all of their arguing over what is going on would be dependent on the design of this specific unit itself. I would sooner pose this question to Nad and/or someone that is knowledgeable of this specific unit if I really wanted to know.

Glad you are enjoying things nonetheless.

Mike

[pearsall001]

Nah, I am not smart enough for all this. Try it without the fancy bi-output and then with it. Listen to some very dynamic music at a high volume and let your ears decide. I just know if I like what I hear or I don't...I am simple folk I guess:)

I personally think that all of their arguing over what is going on would be dependent on the design of this specific unit itself. I would sooner pose this question to Nad and/or someone that is knowledgeable of this specific unit if I really wanted to know.

Glad you are enjoying things nonetheless.

Mike

That's the first thing I did was to shoot an email off to NAD posing the question at hand. Then I posted here to get feedback on the same question. I got a lot of diferent takes on this bi-amping issue. I've read a lot of theory & speculation on the different answers here but I don't know which one or if any of the responses are correct or not. As soon as I hear back from NAD I'll post their answer (hopefully the correct one :D )

[hoosier21]

more bad information from Vr3 :) read more type less

[Deadof_knight]

I don't know if it is my imagination, but this stuff seems to be getting worse around here lately.

It starts becuase we come running in here to check to see what everyone else wrote and to then say something in return hahaha it is entertainment and frustration all wrapped into one lil forum ! ;)

[Dennis Gardner]

New audio term warning!!!!!!!!

I guess the NAD with two power supplies wired this way is giving him Separately Powered, Passively Filtered Biamping.


Put that in your signature Phil!!

[Deadof_knight]

Sweet Dennis !

[heiney9]

New audio term warning!!!!!!!!

I guess the NAD with two power supplies wired this way is giving him Separately Powered, Passively Filtered Biamping.


Put that in your signature Phil!!

Dennis, they use the same power cord so in a sense NOT seperately powered :p:D :)

[Dennis Gardner]

Dennis, they use the same power cord so in a sense NOT seperately powered :p:D :)


Unicorded...........

[dkg999]

Chocolate ice cream tastes like chicken :p

If he hears a difference, there must be a difference. None of you have accounted for the geographical differences in electron composition created by the earth's axial rotation. Depending on where the NAD power supply components are manufactured or the time of the year, they might have the denser molecular properties that are know by many audiophiles to create a sweeter tube-like sound and also enhance the ability of a torridal transformer to supply multiple channels of sound. ;)

[hearingimpared]

Vanilla ice cream tastes like chocolate.

Listen the merits of chocolate ice cream are obvious. It is well documented that most people like chocolate better than vanilla but eat vanilla anyway. Studies have shown that those who actually like chocolate better than vanilla but eat vanilla really love strawberry better but are ashamed to admit it. Now on the other hand a new study has come out that proves without a shadow of a doubt the butter in butter pecan ice cream can be toxic when mixed with the pecans but people who say they like butter pecan ice cream have no problem eating butter almond but with butterscotch syrup on it to counter act the toxicity of the butter in the butter pecan . . .

. . .so what does this all mean . . . YOU ARE WRONG!

:rolleyes: :rolleyes: :D :p ;)

[hearingimpared]

I had to liven things up around here, it was getting too boring!!! :D Anyway, I'm still looking for the magic answer. I don't think anyone's put their finger on the answer yet, just a lot of theory & speculation. Any thoughts??

You did that already when you said it sounded wonderful!

[tonyb]

Far be it for me or anyone else to tell Phil what he hears.As long as it's good to your ears Phil,rock on bro.

[madmax]

Cant we all just go mono... ??
madmax

[F1nut]

Cant we all just go mono... ??
madmax

Hell NO!

[WilliamM2]

Cant we all just go mono... ??

Well...with everyone going back to tubes and vinyl, I guess mono is the next logical step. Why not?:p

[cfrizz]

I'm NOT!!!!:D I have zero interest in going back to the old days.:D

Well...with everyone going back to tubes and vinyl, I guess mono is the next logical step. Why not?:p

[Vr3MxStyler2k3]

I didnt give misinformation. I gave partial information that wasnt complete.

What I said was -- if you do not cross your amps over before they receive their signal, they are still processing and powering a full 20-20hz signal.

Now, this is what I learned on this board ages ago, but the gentleman that told me this neglected to tell me that on a tweeter network, the amp will see a 400kohm load. Which, irregardless -- is still powering a 20-20hz signal, just at a nuch higher impedance...

I didn't give wrong information, you are just being a jerk ;)

To me, all he is doing is basically taking two 2 channel amps and running it into his speakers. Applying alot more power to each individual part. Which of course is going to give more headroom, but still wont have the advantages of active biamping.

Makes more sense to me to just get one large amp ---

But he is definitely applying more power - just not in the sense to me should be called biamping. But whatever. Passive biamping, sure sure...

[dkg999]

Sid - are you a chocolate or vanilla type of dude? That's the important question in this thread :p

[Vr3MxStyler2k3]

I love chocolate ice cream! :)

[danger boy]

i call bi amping Howard

[jdhdiggs]

Amateurs!

I have actively quad amped a system. Actually, if you count the amp plugs into the wall, I hex amped that bitch!

If you are not using a crossover before the amp, you are not providing the speaker with anything other than 1-2 watts of more power. Additionally, if you move the crossover in front of the amps, all you have done is added the 1-2 watts more power to each side and eliminated the harmonic distortion originated on the down side on the crossover slope. Things to research: Ratio of power vs frequency vs. dB (essentially ever octive you drop, you need to double the power output to maintain the same dB level). Another thing to research is how crossovers work. The 400kOhm reading was probably found based on a static resistance reading. Above the x-over frequency, it is around 4-8 ohms. Resistance in these systems means nothing without attaching a frequency to them. One of the common misconceptions around here is to use V=IR for everything without realizing R is a moving target and is different when heading to different parts of the speaker.

The only way you gain significant advantages IMHO is to use different amps with different strengths. For example, in my quad/hex amp I used my Knight mono 35W tub amps on the tweeter section, Counterpoint 170W Hybrid amp for the mids, adcom 565 mono's on the mid-bass/bass and a bash digital for the bass-sub bass. Sounded fantastic once dialed in.

[Yashu]

That is a lot of amps man... but what kind of speakers let you bypass their crossovers and use your own? Sounds like a DIY system.

I don't buy into the "only one to two watts" statement... at least not with all types of speakers, but I do agree about trying to match amps to their strengths.

[jdhdiggs]

Magnepan 3.3R's let me run 3 external crossovers if I want and I added an additional high pass/low pass combo to pull sub 45 Hz info to a sub.

The 1 to 2 watts statement comes from how power is used by a speaker. For simplicity, let's use a simple 2 driver configuration and 2 200W amps. The tweeter will rarely (If ever) take more than 1 or 2 watts. If you are running a watt or more to your tweeters, you're nuts-much more than 2 watts and they'll start melting.

For ease of the example, we'll just say your tweeter section is using 2 watts. The amp powering this section can generate 200 W but if the max signal is 2 W and you blow your speakers at 5 W. What are you doing with the rest of that power?

Now let's look at the lower section: This is where most of the power is consumed. In the mono amp situation the tweeter was pulling 2 watts leaving 198 for the midbass/bass. Now you've eliminated that massive load and can add it to the low end.

Congrats, you've gone from 200W of usable power to 202 watts and doubled your cost. Now you can go into some esoteric designs where this will change a bit, but that's a different ballgame. There's always an exception.

An example of how power cascades to the lower frequencies, here's how my rig was setup (freq ranges are approximate, I can't find the exact numbers right now):

35 W Tweeter (1.7 KHz +)
170W Mid Bass (180 Hz to 2 kHz)
450W Bass (40 Hz to 200 Hz)
900W Sub Bass (<45 Hz)

The 900W maxed out first, then the 450 W amp gave out, then the 170W amp. The amp that had the most loafing was the 35W amp. Now remember, this was a 82dB/Watt system in a 9,000 cubic foot room to even test where the powere would give out. (No I never clipped the amps or popped fuses, I had another method of protection that let me know when it was about to "blow").

[heiney9]

I don't buy into the "only one to two watts" statement... at least not with all types of speakers, but I do agree about trying to match amps to their strengths.

Check out Nelson Pass's First Watt products. There is some truth to low power amps not being right for every type of speaker.

H9

[Yashu]

Well yes of course, not all amps are made for all speakers, and when you combine several different types you run into problems like voice matching and whatnot... I was just thinking of how nice an all tubed mid/HF could potentially sound with the raw power of SS on the bass.

Extra 2 watts aside, I like the idea of using ALL the channels of the amp and better distributing the load, even if just a bit.

[MGPK]

FYI

Bi-Wiring Pros:
Easy; Inexpensive; choice of ideal cable for use (high frequency = low capacitance / low frequency = low resistance); lowered resistance in total cable solution; some perceived improvement in sound in non-scientific tests.

Bi-Wiring Cons:
Questionable effect of one cable on the other since they are connected in parallel (capacitance and inductance of one cable will affect the capacitance of the whole system); not always perceived improvement.

Passive Bi-Amping Pros:
All the same pros as Bi-wiring pros; dedicated power supplies for each driver for improved dynamics and maximum sustained output; improved damping; greater isolation between low and high signals; amplifier technology could be matched to usage (Class-A for treble, High Current/Power for bass); more perceived improvement in sound in non-scientific tests.

Passive Bi-Amping Cons:
Added cost; more difficult as amps must be matched in gain ratio; no improvement in amplifier efficiency; still not 100% perceived improvment sound.

Active/Passive Bi-Amping Pros:
All the pros mentioned above; slight increase amp power supply efficiency; reduction in amp noise; easier to calibrate output levels (assuming crossover has level controls); yet more perceived improvement in sound.

Active/Passive Bi-Amping Cons:
Some passive crossovers designed for shallow slopes requiring crossover to be several octaves outside of crossover point; Few active crossovers have settings for unique crossover points for high pass and low pass (in this design the high pass must be an octave or two high than the passive crossover and the low pass crossover must be an octave or two below the passive crossover); more complicated setup; significant added cost (especially as active crossover must be custom designed for unique crossover points for each output); perceived improvement may not be improvement but perceived difference as setup is quite complex.

Active Bi-Amping Pros:
Most efficient use of amplifier power; maximum damping from amp due to elimination of all passive components; improved phase response (with proper crossover design); faster sound/greater "negative" dynamics (no discharging of fields in capacitors and inductors that cause ringing); nearly 100% perceived improvement of sound.

Active Bi-Amping Cons:
Most commercial loudspeakers are not design nor are easy to actively bi-amp; commercial speakers often have tuning circuits in passive crossovers that are not easily replicated with active crossovers requiring EQs; Very complex to tune; Fixed matching high pass and low pass slopes cannot take into account acoustical slopes inherent in drivers; Expensive.

[GV#27]

Good informative post MGPK,I can vouch for the improvements wrought by going fully active.

My set up is now fully active and the change has been worth the added complexity.I now hear more detail, the system can play louder without stress ,reduced distortion with far less listening fatiuge when played at higher levels.

Im using relatively small amps for more the mids and tweets (60 watt Bryston 2B LP's)and they are usually just loafing along and almost never run into clipping.The odd loud movie sound track will cause brief clipping in the mid amp.

The woofers are driven by a 120 watt Bryston 3B that seems to be just enough clean power to drive them without constantly running into clipping. The active crossover's slopes and xover points where optimized for the drivers Im using which is very important.
So Im convinced properly done,active offers big gains in SQ.

[jdhdiggs]

MGPK:

Since I have not noticed you before, let me say:

Welcome, you are DEFINATELY a welcome addition to the board!