or Connect
AVS › AVS Forum › Audio › Audio theory, Setup and Chat › Question on bi-amping
New Posts  All Forums:Forum Nav:

Question on bi-amping - Page 9

post #241 of 1039
Quote:
Its a feature that probably sells a few AVRs.

Okay, so bi-amping features on receivers can't actually improve power output? If that's the case then it would seem to me to be a great waste of time.

post #242 of 1039
Quote:
Originally Posted by Shaun B View Post
 
Quote:
Its a feature that probably sells a few AVRs.

Okay, so bi-amping features on receivers can't actually improve power output? If that's the case then it would seem to me to be a great waste of time.

 

Hold that thought!

 

But be aware that this is so-called passive biamping that is a waste of time. proper biamping, with active electronic crossovers, is a different thing altogether.

post #243 of 1039
Quote:
Originally Posted by amirm View Post

If that manufacturer provides the crossover settings for you, then you are golden and the work is trivial.

I already know crossover point and have seen the crossover slopes from my own frequency response measurements of the speakers as standard. I assume adjustable parameters with a miniDSP would be crossover point, slope, gain, and time alignment?
post #244 of 1039
Quote:
Originally Posted by arnyk View Post

How is that different than engineering good speakers with passive crossovers? A passive crossover needs to not only tune the crossover frequency, but needs the designer to equalize the frequency-response of the speakers, adjust their phase, etc.

As you have already said, it is different because the drivers themselves interact with the components in a passive crossover and the speaker designer is much more limited in the types of corrections that can be made with a passive crossover. With an active crossover (especially a DSP based one) many more corrections can be applied (without the side effects present in a passive crossover) so that the driver responses can be much closer to ideal. Both the signal from the crossover and the amplifier (power, damping, etc) can be optimized for each driver as they are all known quantities and designed to work together. Are you really arguing that the design of powered speakers has no advantage over those with passive crossovers?

Quote:
Originally Posted by arnyk View Post

Most current production active subwoofers still use Class AB amplifiers. For all practical purposes there are no such things as digital amps - under the covers they are class AB, G or D which all have analog inputs and outputs and are analog in-between.. The small but increasing number of switchmode amps (class D) are not digital because they operate entirely in the analog domain.

Yes, I said "Class D" which most of us refer to in slag as "digital amps" (at least the audio designers that I've worked with do). Yes, they have analog inputs (obviously) and have analog outputs (doubly obvious) and they use fast switching between two voltages (digital switching) to supply an amplified output that follows the input.

Quote:
Originally Posted by arnyk View Post

In general the only way that happens is if you do something pretty silly anyway and use the AVR's direct mode.

Not true. This happened to me every time I (and thousands of others) selected the multi-channel input on an AVR. No doubt a cost reduction decision not to include ADC conversion on incoming MC inputs since bass management was obviously done in the digital domain only.

Quote:
Originally Posted by arnyk View Post

Wrong. Stereo sources don't always skip bass management.. You have to engage a special feature for that to happen. My last two AVRs have lived their lives with only stereo or digital sources and have had bass management active all of the time.

Wrong, you don't have to engage anything if the AVR doesn't convert analog sources. And you are the only one that used the word "always".

Quote:
Originally Posted by arnyk View Post

I could hope to educate you to forget about outboard surround decoders but you've already ignored enough of my corrections and updates to your posts to educate me about the probability of that ever happening. ;-)

I don't have an "outboard surround decoder" (unless "outboard" to you means outside of an AVR). Mine is inside my BD player which is connected directly to amps. Not every uses AVRs even though they are the most economical - but audio isn't about economy for me, it is about the flexibility of my components to do what I want them to do. That is why I don't buy AVRs.

Arny, I'm not an idiot. If you don't want to argue with me then don't.
post #245 of 1039
Hi Shaun,
Quote:
Originally Posted by Shaun B View Post

. . . I know my receiver in my bedroom offers bi-amping facility... you have to connect the surround back L+R to the fronts, or some such thing, and toggle bi-amp mode
It might actually be useful.

The first requirement would be that the speakers support bi-amping; ie: disabling the passive crossover. Since all AVRs contain the enough amps and also contain a DSP, and most of them support some form of equalization, all it would take would be extra firmware to implement an active crossover.

That feature might actually be real.
post #246 of 1039
Quote:
Originally Posted by MarkHotchkiss View Post

The first requirement would be that the speakers support bi-amping; ie: disabling the passive crossover.

What speakers specifically support disabling the crossovers? Don't you just remove them or bypass the wiring straight to the drivers? This can be done to almost any speaker?


Quote:
Since all AVRs contain the enough amps and also contain a DSP, and most of them support some form of equalization, all it would take would be extra firmware to implement an active crossover.

But you also said... "The benefit may be minimal, and it takes a lot of expertise to get it right."

So wouldn't adding that feature to mass market AVRs only cause a lot of headaches for a lot of people if it isn't actually that easy to do well?
post #247 of 1039
Hi Kiwi,
Quote:
Originally Posted by kiwi2 View Post

What speakers specifically support disabling the crossovers? Don't you just remove them or bypass the wiring straight to the drivers? This can be done to almost any speaker?
I used the word "disabling" because it would be different for different speakers. It would have to be a multi-way speaker to begin with. On some speakers it will simply be a matter of removing the straps. At the other extreme, you would need to open the speaker up, physically disconnect the passive crossover and add additional posts for the second set of connections.

Quote:
But you also said... "The benefit may be minimal, and it takes a lot of expertise to get it right."
Yes this is true. The benefits may be minimal, if the passive crossover was a good match to begin with. If the passive crossover was not, then bi-amping may make a big improvement in the frequency-response and phase, if you know what you are doing or are somewhat lucky.

Quote:
So wouldn't adding that feature to mass market AVRs only cause a lot of headaches for a lot of people if it isn't actually that easy to do well?
Well, yes it could. But that's for the marketing people to decide. wink.gif

The firmware could also be added to "build" the crossover with the aid of a microphone, similar to the room-correction firmware. The already existing room-correction firmware may be able to pull it off itself, if told where the crossover frequency should be.
post #248 of 1039
Quote:
Originally Posted by MarkHotchkiss View Post

I used the word "disabling" because it would be different for different speakers... ...On some speakers it will simply be a matter of removing the straps.

I was wondering if you were confusing double posts with straps as an easy way to bypass the crossover. Removing the straps does not bypass the speaker's crossover.

A lot of people had this misunderstanding and confusion even earlier on in this very thread... www.avsforum.com/t/1492314/question-on-bi-amping/150#post_23789570
post #249 of 1039
Quote:
Originally Posted by vinyl View Post

There was an interesting discussion on this subject by a reputable professional - then again - perhaps he’s just pumping amps.

http://www.audioasylum.com/cgi/vt.mpl?f=amp&m=160551

Which says:
Quote:
Originally Posted by Ole Lund Christensen 
The voltages are still the same, but the currents are not.

True
Quote:
Originally Posted by Ole Lund Christensen 
This happens because the capacitor in the tweeter crossover stop the bass current from flowing in the output transistors.

True
Quote:
Originally Posted by Ole Lund Christensen 
So the tweeter sound will be cleaner, because the 20-100 Hz heavy bass currents are not present in the tweeter amplifier channel.

True, but the real question is the difference large or microscopic or what?
Quote:
Originally Posted by Ole Lund Christensen 
The reduction of distortion can be 10-20dB by using this setup.

Sounds impressive until you know what it actually means, which the author does not give, no doubt intentionally.

First off, while the reduction of distortion can be 10-20dB with a super-crapola amplifier, it is vanishing with a good amplifier. Secondly a reduction of 10-20 dB means nothing until we know what the reduction is taken from. If the amplifier is again crapola with -40 dB distortion, a 20 dB reduction takes us to -20 db which is pretty dire. If the amplifier is typical with -80 dB distortion, then a 20 dB reduction takes us to -60 dB which is OK. However if the amplifier is good, there is no 20 dB reduction, but rather the reduction is negligible, and negligible minus negligible is negligible.

The author must know the relevant details but presents them in a questionable way, probably in order to trick his readers into presuming an improvement wich in reality does not exist.. He could show a real world example with real numbers because presumably he did some real world tests, but does not do so.

Quote:
Originally Posted by Ole Lund Christensen 
SMPTE distortion using 60Hz and 7kHz tones at the same time will almost be gone.

let me remind you that the baseline in this discussion is a good amplifier driving a real world speaker. If passive biwiring actually had some signficiant effect simply hooking the speaker to the amplifer would raise the amplifier's distoriton to an audible level which we already know does not happen.
post #250 of 1039
Quote:
Originally Posted by kiwi2 View Post

Quote:
Originally Posted by amirm View Post

If that manufacturer provides the crossover settings for you, then you are golden and the work is trivial.

I already know crossover point and have seen the crossover slopes from my own frequency response measurements of the speakers as standard. I assume adjustable parameters with a miniDSP would be crossover point, slope, gain, and time alignment?

That plus equalization and filter Q.
post #251 of 1039
Arny - thanks for taking the time reading the Asylum thread - your commentary gives it new perspective.
.
FWIW - I run Maggies 1.6 passively biamped with 2 Crown K1’s - aside from channel separation - I do believe the bass has more authority.

I have always enjoyed your no-nonsense approach.
post #252 of 1039
Hi Kiwi,
Quote:
I was wondering if you were confusing double posts with straps as an easy way to bypass the crossover. Removing the straps does not bypass the speaker's crossover.

A lot of people had this misunderstanding and confusion even earlier on in this very thread... www.avsforum.com/t/1492314/question-on-bi-amping/150#post_23789570
Yes, that's a very good point.

There is indeed a crossover in the speakers that have two sets of binding posts, and are connected with straps. However, to be a little anal with the terminology, when the straps are removed, it can't really "crossover", can it. What you have when the straps are removed are a pair of filters: a high-pass filter for the upper-frequency drivers, and a low-pass for the lower-frequency drivers.

Unless you wish to change the frequency of the active crossover to be different from the original crossover-frequency, then the filters that remain in the speakers are not a big concern. They will affect the frequency-response and phase as they did before, and the active crossover will need to take that into account. The tuning of the DSP filter would be very different, depending on whether or not you left those filters intact.

My personal approach would be to remove the original filters from the speakers, so that all of the compensations are done in the DSP. But that's me, I'm a DSP guy.
post #253 of 1039
Leaving the passive filters connected inside the speakers would prevent any improvement from active bi-amping - the passive filters would interact with any frequency response changes you tried to make with an upsteam active crossover and the filter slopes would add together with unpredictable results - not a good idea.

Without bypassing the internal crossovers, you would be "stacking" passive bi-amping and active bi-amping when you don't know anything about the internal passive filters.
post #254 of 1039
Quote:
Originally Posted by MarkHotchkiss View Post

There is indeed a crossover in the speakers that have two sets of binding posts, and are connected with straps. However, to be a little anal with the terminology, when the straps are removed, it can't really "crossover", can it. What you have when the straps are removed are a pair of filters: a high-pass filter for the upper-frequency drivers, and a low-pass for the lower-frequency drivers.

Unless you wish to change the frequency of the active crossover to be different from the original crossover-frequency, then the filters that remain in the speakers are not a big concern.

Crossover/high-pass low-pass filters, same thing. Removing the straps does not bypass anything.

I have never heard of anybody going to active and leaving the passive crossover in the chain as well.

Have you done a speaker conversion from passive to active yourself or is your opinions on this simply from reading other people's options on interweb forums?

..
Edited by kiwi2 - 11/10/13 at 8:25pm
post #255 of 1039
I don't know the last time I saw a sub with class AB amp. These were obsoleted years ago with the availability of ICE (class D) modules and such. It is a marriage made in heaven since the class D amps have lowest impedance in low frequencies and of course are highly efficient. In addition, the output filter of the class D amp can be designed to match the sub's driver. This gives the target response and helps reduce EMI problems substantially. So the statement that "Most current production active subwoofers still use Class AB amplifiers. " is decidedly stale and wrong with respect to the audiophile market today.
post #256 of 1039
Quote:
Originally Posted by kiwi2 View Post

Crossover/high-pass low-pass filters, same thing. Removing the straps does not bypass anything.

I have never heard of anybody going to active and leaving the passive crossover in the chain as well.

Have you done a speaker conversion from passive to active yourself or is your opinions on this simple from reading other people's options on interweb forums?

Well, technically, I think the other statment is correct. A crossover is composed of (in the case of a two-way) a high pass and low pass filter working together. Neither of those operating separately would be a crossover.

I think it's not terribly uncommon to at least leave a capacitor before a tweeter....in case of accident it at least might have a chance to survive. That cap would be a HPF. Even if the crossover remains in the speaker surely there is some benefit of not having the amps swing a full range signal.

Also, JBL provides biamp tuning parameters for my SR4732A speakers even though it's clear by the schematic that none of the crossover is bypassed. Only the woofers are separated from the mid and high, pretty much just like removing the straps.
post #257 of 1039
Hi Mtn-tech,
Quote:
Originally Posted by mtn-tech 
Leaving the passive filters connected inside the speakers would prevent any improvement from active bi-amping
On the contrary, it would not prevent improvement, it would simply change the nature of the improvements that are required, and typically simplify the DSP tuning.
Quote:
. . . the passive filters would interact with any frequency response changes you tried to make with an upsteam active crossover and the filter slopes would add together with unpredictable results - not a good idea.
While not saying it's a good idea, I will say that the active crossover and the filters internal to the speaker would add together with completely predictable results. Specifically, any slope in the active crossover would add to the slopes in the HPF and LPF within the speakers. That means that you could preserve the original slopes or you could increase the slopes. What it also means, however, is that you cannot decrease the slopes or change the crossover frequency.
Quote:
Without bypassing the internal crossovers, you would be "stacking" passive bi-amping and active bi-amping when you don't know anything about the internal passive filters.
First of all, we stack filters all of the time. There is nothing difficult or bad about it. Filters are completely additive.

Second, you don't need to know about the internal passive filters. All you need to know is what your measurement software tells you about their effects. You then compensate using the same method you would if those passive components were not there.


Hi Kiwi,
Quote:
Originally Posted by kiwi2 View Post

Crossover/high-pass low-pass filters, same thing. Removing the straps does not bypass anything.
Removing the straps prevents the filters from acting as a crossover. Yes, a crossover is a pair of filters (or three filters). No, a pair of filters are not a crossover unless they are wired together as such. Not the same thing.
Quote:
I have never heard of anybody going to active and leaving the passive crossover in the chain as well.
See WhoArU's post above. What do you think is the purpose of the double binding-posts and straps?
Quote:
Have you done a speaker conversion from passive to active yourself or is your opinions on this simple from reading other people's options on interweb forums?
Neither. This is based on what I have been asked to design. Designing DSP systems is some of what I do for a living.


Now let's talk about the advantage that the passive filter provides that the active filter cannot - compensating for the reactive nature of the drivers. Some components of the passive crossover are there to control the phase of the impedance seen by the amplifier. Too much inductance, inherent in the magnetic nature of a speaker, causes phase lag that can be difficult for the amplifier. The speaker designers attempt to control this phase in the crossover, and its removal is not something that can be compensated for in an active crossover.
Edited by MarkHotchkiss - 11/10/13 at 8:14pm
post #258 of 1039
Quote:
Originally Posted by whoaru99 View Post

I think it's not terribly uncommon to at least leave a capacitor before a tweeter..

Except the one in there at the moment rolls off just above 1k with a certain slope. I believe people who leave a capacitor before a tweeter are ones that roll off above 20k to stop ultrasonics.
post #259 of 1039
Quote:
Originally Posted by amirm View Post

I don't know the last time I saw a sub with class AB amp. These were obsoleted years ago with the availability of ICE (class D) modules and such. It is a marriage made in heaven since the class D amps have lowest impedance in low frequencies and of course are highly efficient. In addition, the output filter of the class D amp can be designed to match the sub's driver. This gives the target response and helps reduce EMI problems substantially. So the statement that "Most current production active subwoofers still use Class AB amplifiers. " is decidedly stale and wrong with respect to the audiophile market today.

In the interest of helping you out with that little problem that you have Amir, here's a page full of pictures of them, all current production, all currently for sale at retail:

http://www.parts-express.com/cat/subwoofer-plate-amplifiers/332

The ones marked BASH or Class D (about half of them) are not class AB.

Many of the class AB subwoofer amps use chip amps such as the LM 3886 which are Class AB.

Here is another listing of plate amps from a well-known supplier of high quality subwoofers;

http://www.rythmikaudio.com/amplifiers.html

"Our A series amplifiers are class AB, and H series use class H." Class H is essentially class AB with a dynamic power supply,

To summarize there is no doubt that Class D or switchmode amps are well represented and possibly destined to take over most of the market in a few years, but a broad-based observer still sees a lot of classic linear power amps on powered subwoofers,

Finding this stuff just takes a little Google searching.
post #260 of 1039
Quote:
Originally Posted by mtn-tech View Post

Leaving the passive filters connected inside the speakers would prevent any improvement from active bi-amping - the passive filters would interact with any frequency response changes you tried to make with an upsteam active crossover and the filter slopes would add together with unpredictable results - not a good idea.

The interaction would happen but it would be entirely predictable.

Quote:
Without bypassing the internal crossovers, you would be "stacking" passive bi-amping and active bi-amping when you don't know anything about the internal passive filters.

Finding out what the internal filters are is trivial. You unsolder the parts at at least one end, and measure them using several economical alternative techniques, and there you go.

The strongest reason for removing the internal filter is to not put them there in the first place, and save their costs. Parts that are large, expensive, may have inherent reliability issues, or are difficult to obtain with stable and precise values should be the first to go. Those would be the LF crossover coils and capacitors.
post #261 of 1039
Claim was "Most current production active subwoofers still use Class AB amplifiers. " There are no production subwoofers at that parts express link. Those are components for DIY subs and yes, both types are available.but that has nothing to do with popularity of class AB amps and certainly not remotely representative of "production subwoofers." No one said you can't buy class AB amps for subs or that class AB subs do not exist. Simply saying that your statement is rooted in knowledge that is years old and doesn't reflect reality.
post #262 of 1039
Quote:
Originally Posted by MarkHotchkiss View Post

Removing the straps prevents the filters from acting as a crossover. Yes, a crossover is a pair of filters (or three filters). No, a pair of filters are not a crossover unless they are wired together as such. Not the same thing.

A HPF and LPF is a crossover.

Quote:
What do you think is the purpose of the double binding-posts and straps?

For people who want to bi-wire or passively bi-amp.

Quote:
Now let's talk about the advantage that the passive filter provides that the active filter cannot - compensating for the reactive nature of the drivers. Some components of the passive crossover are there to control the phase of the impedance seen by the amplifier. Too much inductance, inherent in the magnetic nature of a speaker, causes phase lag that can be difficult for the amplifier. The speaker designers attempt to control this phase in the crossover, and its removal is not something that can be compensated for in an active crossover.

Ok, this is informative and will be an aspect I will need to learn about and research.
post #263 of 1039
Quote:
My personal opinion is that there is only one reason to bi-amp: To discard the passive cross-over in the speaker and replace it with an active crossover prior to the amps.
Quote:
I used the word "disabling" because it would be different for different speakers. It would have to be a multi-way speaker to begin with. On some speakers it will simply be a matter of removing the straps. At the other extreme, you would need to open the speaker up, physically disconnect the passive crossover and add additional posts for the second set of connections.
Quote:
Now let's talk about the advantage that the passive filter provides that the active filter cannot - compensating for the reactive nature of the drivers. Some components of the passive crossover are there to control the phase of the impedance seen by the amplifier. Too much inductance, inherent in the magnetic nature of a speaker, causes phase lag that can be difficult for the amplifier. The speaker designers attempt to control this phase in the crossover, and its removal is not something that can be compensated for in an active crossover.


MarkHotchkiss, you seem to be making things as you go along and that you really don't know what you are talking about. When I pointed out that removing the straps doesn't bypass the passive crossover, you now seem to be changing your tune and that someone should leave the passive filters in place.
post #264 of 1039
Quote:
Originally Posted by amirm View Post

Claim was "Most current production active subwoofers still use Class AB amplifiers. " There are no production subwoofers at that parts express link.

Amir, you are claiming what you can't know, which is how many of the Parts Express products have a dual life inside production subwoofers. Not the least bit unusual.

Retailers like Parts Express rarely provide or even specify the details of the designs or oversee the manufacture of anything - they sell existing products. The existing products are typically originally designed for the OEM market. Some OEMs such as SpeakerPower (a provider of exclusively switchmode devices) are somewhat public about how they address the OEM market.

Typcially more advanced features like switchmode come onto the marketplace starting with high end products, and your association with a high end retailer may bias your perceptions.
Quote:
Those are components for DIY subs and yes, both types are available.but that has nothing to do with popularity of class AB amps and certainly not remotely representative of "production subwoofers." No one said you can't buy class AB amps for subs or that class AB
subs do not exist. Simply saying that your statement is rooted in knowledge that is years old and doesn't reflect reality.

Of course Amir you then continue the obfuscation of the facts by not touching the link to parts from a producer of production subwoofers.

Your post's big mistake was a common one - trying to overcome facts with hyperbole.

I didn't put a gun to your head and make you say: "I don't know the last time I saw a sub with class AB amp. These were obsoleted years ago with the availability of ICE (class D) modules and such.."

That's simply not true if someone would actually take your post at face value. You could have recovered some credibility by backpedalling, but you continued to try to overcome my first example with more hyperbole and completely ignored the truth in my second example and pretend that it doesn't exist. That is fail and fail! Better luck next time! ;-)
Edited by arnyk - 11/11/13 at 4:23am
post #265 of 1039
Quote:
Originally Posted by kiwi2 View Post

Except the one in there at the moment rolls off just above 1k with a certain slope. I believe people who leave a capacitor before a tweeter are ones that roll off above 20k to stop ultrasonics.

A cap left before the tweeter is typically a HPF, intended to protect the tweeter from inadvertent application of LF. That LF could come by accidentally connecting the LF amp to the tweeter or of someone setting the HPF too low (by accident or ignorance) and smoking the tweeter.
post #266 of 1039
Quote:
Originally Posted by kiwi2 View Post

Quote:
My personal opinion is that there is only one reason to bi-amp: To discard the passive cross-over in the speaker and replace it with an active crossover prior to the amps.
Quote:
I used the word "disabling" because it would be different for different speakers. It would have to be a multi-way speaker to begin with. On some speakers it will simply be a matter of removing the straps. At the other extreme, you would need to open the speaker up, physically disconnect the passive crossover and add additional posts for the second set of connections.
Quote:
Now let's talk about the advantage that the passive filter provides that the active filter cannot - compensating for the reactive nature of the drivers. Some components of the passive crossover are there to control the phase of the impedance seen by the amplifier. Too much inductance, inherent in the magnetic nature of a speaker, causes phase lag that can be difficult for the amplifier. The speaker designers attempt to control this phase in the crossover, and its removal is not something that can be compensated for in an active crossover.


MarkHotchkiss, you seem to be making things as you go along and that you really don't know what you are talking about.
Kiwi, don't confuse my personal opinion (which I clearly state) with the technical information that I'm posting. The top quote is my opinion. The other two are facts as I know them. If you think the bottom two are incorrect in some way, we can discuss it. If you don't agree with my opinion, you are entitled to have your own. No need to get insulting. After 40 years of engineering, that is the first time I've been accused of not knowing what I'm talking about.
Quote:
When I pointed out that removing the straps doesn't bypass the passive crossover, you now seem to be changing your tune and that someone should leave the passive filters in place.
I made no such recommendation. I've made no recommendations at all. When the issue was broached, I simply stated the reasons that it was not neccessary to remove the filters inside the speakers. I gave advantages and disadvantages of both approaches, and pointed out one situation where removing the filters could cause problems.

If you think that looking at both sides of an issue is "changing your tune", then it's a good thing you're not in engineering.
post #267 of 1039
I think the percentage of conventional speaker owners who have bypassed the crossovers in their (likely) already well-engineered speakers has got to be tiny.
post #268 of 1039
Quote:
Originally Posted by sivadselim View Post

I think the percentage of conventional speaker owners who have bypassed the crossovers in their (likely) already well-engineered speakers has got to be tiny.


+1

That matches up with what I've seen in my travels.

Converting a speaker from passive to active would make a nice science fair project, and like that.
post #269 of 1039
Ok so what I've understood so far about Bi-amping is>



* A passive crossover is designed to see 100W TOTAL power> adding another 100 watts would only be disipated as heat because it only accept 100W TOTAL (not 200W) anyways

If the internal crossover has Separate passive components going to each speaker> then it's still only handles 100W total. Except in Bi-amp ~ now the woofer can see a full 100% 50 Watts of power and the tweeter will use 20% @ 50WATTS.

Basically the issue then lies in having the woofers use100% of available power from the amp instead of lets say 60-75% power (that the tweeter midrange need).

So in essence although doubling the power in total will not yield doubling of power> it will allow the low end to use all available power instead of sharing it with the tweeter.

Single amp @ 100W = 60-70*WATTS @ (Woofer) + 20-30WATTS @ (Tweeter / Mid)

Bi-AMP @100+100 = 50-60WATTS @ (WOOFER) + 20-30 WATTS @ (TWEETER / MID)

*It would help to contact the Manufacturer of the speakers and ask how much power the Low x-over and High x-over can handle when fed separate power feeds for bi-amping.

Personally I would think that: take for example my Paradigm Monitor 11's can handle 280 Watts total RMS. >Then Adding an amp that puts 140WATTS RMS to the woofer section and another amp @ 100 Watts for the Mid tweet section would yield better acoustics theoretically ~ than an amp that would lets say only do 140 WATTS RMS (200W Peak) Assuming both amps where evenly matched in terms of voltage output so there's no delay between the two signals going into the Speaker cabinet etc.





____
Edited by theatredaz - 11/11/13 at 6:34pm
post #270 of 1039
Quote:
Originally Posted by amirm View Post

I don't know the last time I saw a sub with class AB amp. These were obsoleted years ago with the availability of ICE (class D) modules and such. It is a marriage made in heaven since the class D amps have lowest impedance in low frequencies and of course are highly efficient. In addition, the output filter of the class D amp can be designed to match the sub's driver. This gives the target response and helps reduce EMI problems substantially. So the statement that "Most current production active subwoofers still use Class AB amplifiers. " is decidedly stale and wrong with respect to the audiophile market today.

Same here. I just finished several weeks of research to find the right sub. One of them (but only one out of dozens) on my list had a Class AB amplifier - the Martin Logan Dynamo 1000w. It had claims that its "class AB output stage" was better than a Class D amplifier - for a subwoofer, I doubt that but I'm sure it uses a lot more power. It also claimed "lower distortion and less noise than typical Class D switching amplifiers" which could be true but with a subwoofer I'm sure you wouldn't be able to hear it.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Audio theory, Setup and Chat
AVS › AVS Forum › Audio › Audio theory, Setup and Chat › Question on bi-amping