[audiotom]

Was curious about vertical biamping of Salk ss10s

I plead ignorance up front

Dennis and Jim,

Would this require an active crossover for the signal path between the preamp and amps?

As I understand it each amp would have one channel doing bass frequencies and the other treble and mid range. Is there a desired crossover element that matches the speakers crossover?
Have you built any prototype crossovers?

Thanks

[pstrisik]

Good topic audiotom. 

I'm working on bi-amping myself, but not with active xovers.  If your amps are the same, you could bi-amp as you describe, just using the passive xovers and the existing double speaker terminals.  Appropriate active xovers would be preferable, but I think you have to bypass the passives to make it worth it (Dennis and Jim please correct me if I'm wrong). 

I actually have two different amps that I will be using to bi-amp my SS8s.  Both are Conrad-Johnson, but the amp I will use for the bass is solid state (MF-2350A) and the amp for the mids/highs is tube (Premier 11A).  I have a high quality attenuator on the way and will make an attenuator box with RCA in and out. This will allow me to match the gain by reducing the gain of the louder one.

If your two amps are the same, btw, I would power each speaker with one amp rather than one channel from each amp to each speaker.  This should eliminate any crosstalk - effectively running the amps as monoblocks.


.......Peter

[audiotom]

Peter

cool

thanks for the insight

The option you are considering doing is horizontal biamping and I like the idea of going solid state on the low end. tube on high. Having a higher wattage solid state amp with more low end slam to handle both channels of bass, will also free up the high end tube amp to shine with less power constraints.

i am currently running solid state mono blocks and I have a second tube hybrid stereo amplifier. I run both in a bi-wire configuration. 

For vertical biamping that I am considering, I take it not using active crossovers on the vertical biamping - one amp with one channel doing one speakers high end and the other channel the low end - would drain more power from the amp - but in an even fashion.

what I was considering doing was to get the frequencies separated at the amp level so the signal going to the speakers is clean with the treble section not overloaded by the bass power requirements.

Tom

[pstrisik]

You raise something I hadn't considered, but haven't heard anyone mention before, so I'm not sure it is an issue.  That is the uneven power draw from each amp if vertically bi-amping.  One channel from each amp is doing bass so each amp has one channel with greater demand on it.

I think active bi-amping is considered to be a better sonic option (if the active xovers are done well).  But I'm not sure we would gain much to do active xover then feed into the passive xover.  I read a while back what the inherent downside to passives was, but no longer recall. 

.......Peter

[audiotom]

Peter

I just hate to think the high frequency channel would be getting the same signal and hence driven over the whole frequency spectrum

then again without the active crossover upfront, isn't this essentially a mono block?

I'm looking at the possibility of utilizing my hybrid tube amp and getting more power to drive the speakers.
Unfortunately the amp has been upgraded to a new model, so to get a matching pair I'd have to wait to find one on the used market.

[pstrisik]

The existing passive xovers keep the hi/mid drivers from getting low frequencies.  But the amp is producing them before it is filtered out.  Perhaps that is the reason passives are considered less efficient/desirable. 

I'm in the same boat if I were to vertically bi-amp.  I would have to find another C-J 11A (circa mid 1990's).  They don't come up too often.

........Peter

[audiotom]

Jim and company are more than likely loaded up and heading out west to RMAF as we speak.
Can't wait to hear how the show goes.
This can wait...

[Big Red Machine]

Jim and company are more than likely loaded up and heading out west to RMAF as we speak.
Can't wait to hear how the show goes.
This can wait...

He's picking me up in a just a couple minutes.  20 hours of diving.  Over 1500 lbs of goodies.

WRT bi-amping - IMO not worth the effort vs the benefit.

[audiotom]

Have a great trip Pete,

I'm sure you and Nuance will enjoy showing the latest wares

Give Jim and Mary a shout out and blessings from our way

Which speakers is he taking?

SS8s would really be a giant slayer at RMAF

[Nuance]

WRT bi-amping - IMO not worth the effort vs the benefit.

^ This.  YMMV, of course.

[pstrisik]

It seems this opinion is not too different from saying it is not worth the effort to double the power and it would not be worth it to move from a stereo amp to monoblocks.

........Peter

[Nuance]

It seems this opinion is not too different from saying it is not worth the effort to double the power and it would not be worth it to move from a stereo amp to monoblocks.

........Peter

Huh?  Doubling the power sounds good to me, as does moving to monoblocks (although the latter is less important IMO).  Doubling the power = more headroom, so that's a good thing.  You won't hear a difference in sound, but you'll increase the changes of not clipping the amps.

[pstrisik]

Yes, bi-amping means using two amps instead of one.  (Are you by any chance thinking of bi-wiring?)  For example, if I am running a 125wpc amp and decide to bi-amp, I would get a second (same for the sake of argument) 125wpc amp and use one amp for left and one for right.  The left channel output of one amp would go to one pair of terminals on one speaker and the right channel output to the other pair of terminals on the same speaker (with jumper bars removed of course), same for the other speaker with the other amp.  Now you have 250wpc with complete channel separation ala monoblocks.  This is what audiotom referred to as horizontal bi-amping.  Vertical bi-amping would likely be with two different amps (ideally gain matched) with one amp powering the top terminals on each speaker (highs/mids) and the other powering the bottom terminals (bass).  You still get the extra power and some benefit of division of labor with one amp powering the hi/mid drivers not having to work so hard since the bass is handled by the other amp, but you don't get the benefit of reduced crosstalk in this case.

Sorry if I'm restating stuff you already know.

My plan, as soon as I get my attenuator and build the box, is to use a 75wpc C-J Pre11A tube amp for the hi/mid and a 125wpc C-J 2250A solid state for the bass.  I'm hoping to really benefit from the excellent midrange and smoothness of tubes and the tight control of bass of solid state.

..........Peter

[srb]

For many speakers, passively bi-amping often doesn't yield as much improvement as replacing a single amplifier with one of double the power because the power requirements of the woofer always greatly exceed that of the mid/high drivers.  Simply adding a second amplifier might only make an additional 10% to 20% power available to the woofer, whereas an amplifier of twice the wattage and power supply capacity might make 80% to 90% more power available to the woofer.
 
The lower the crossover point, the greater the possible gain.  The SoundScape has potentially more to gain than the HT2-TL or SongTower as do many 3-way speakers compared to their 2-way counterparts, or the few rare 2-way speakers with extremely low crossover points.
 
In my own experience, I have experimented with passive bi-amping a variety of 2-way speakers with identical amplifier channels, and although some of the time a small improvement was heard, substituting an amplifier of twice the power had a much greater effect.
 
Passively bi-amping with different amplifiers, such as solid state on the woofers and tubes on the mid/high drivers, goes beyond just increased power availability though, and adds the possibility of voicing the mid/highs with different tonality and soundstage characteristics.
 
Steve

[pstrisik]

  Thank you!

.......Peter

[audiotom]

Peter

it seems like it should be the opposite - visually

you have the two bi-amp options switched around

Vertical bi-amping  - one stereo amp per speaker
Horizontal bi-amping - one stereo amp for bass, one stereo amp for mids and highs

Steve

In this situation, I would like the sound characteristics of an amp that doesn't have an upgrade to higher power but can be biamped.

[woodsyi]

Peter

it seems like it should be the opposite - visually

you have the two bi-amp options switched around

Vertical bi-amping  - one stereo amp per speaker
Horizontal bi-amping - one stereo amp for bass, one stereo amp for mids and highs

Steve

In this situation, I would like the sound characteristics of an amp that doesn't have an upgrade to higher power but can be biamped.

They don't have to be stereo amps -- two identical monoblocks in place of one stereo amp would do just fine.   

[pstrisik]

Peter

it seems like it should be the opposite - visually

you have the two bi-amp options switched around

Vertical bi-amping  - one stereo amp per speaker
Horizontal bi-amping - one stereo amp for bass, one stereo amp for mids and highs

Steve

In this situation, I would like the sound characteristics of an amp that doesn't have an upgrade to higher power but can be biamped.

I don't know what's "official" terminology.  Vertical could refer to amps one up and and one down (I've heard it referred to as "Heaven and Hell" setup  ) or it could refer to one amp setup to power vertically (one amp per speaker).  As the bard said, "What's in a name?  A rose is a rose is a rose."  (I might have butchered Shakespeare too though!  ).

.........Peter

[Big Red Machine]

For many speakers, passively bi-amping often doesn't yield as much improvement as replacing a single amplifier with one of double the power because the power requirements of the woofer always greatly exceed that of the mid/high drivers.  Simply adding a second amplifier might only make an additional 10% to 20% power available to the woofer, whereas an amplifier of twice the wattage and power supply capacity might make 80% to 90% more power available to the woofer.
 
The lower the crossover point, the greater the possible gain.  The SoundScape has potentially more to gain than the HT2-TL or SongTower as do many 3-way speakers compared to their 2-way counterparts, or the few rare 2-way speakers with extremely low crossover points.
 
In my own experience, I have experimented with passive bi-amping a variety of 2-way speakers with identical amplifier channels, and although some of the time a small improvement was heard, substituting an amplifier of twice the power had a much greater effect.
 
Passively bi-amping with different amplifiers, such as solid state on the woofers and tubes on the mid/high drivers, goes beyond just increased power availability though, and adds the possibility of voicing the mid/highs with different tonality and soundstage characteristics.
 
Steve

Bingo!!!

[jsalk]

Just arrived in Denver and will be setting up for RMAF in the morning...

There are a couple of comments I should make here...

First, with a speaker like the HT2-TL's, there isn't much to be gained from bi-amping.  The tweeters draw very little power.  So it is doubtful any amp would drive the woofers any better if the tweeter was removed from their output.  The tweeter could perhaps be a little cleaner on its own channel (depending on the amp), but I don't think that any increase in sound quality would be justified by the cost.

For a 3-way speaker, the case is different (although even the tweeter/midrange combination draws relatively little power compared to the woofer section).

Just to make things clear, each driver has its own crossover which limits the frequencies going to that particular driver.  So if you have a separate amp driving each section, each of the drivers is still getting the same basic frequencies as before.  Each crossover for each driver basically takes a full-range signal on its input and filters that signal so that only the appropriate frequencies are fed to its associated drivers

Of course, the volume of each signal sent to each driver is based on each section of the crossover being fed the same power (which is the case with a single amp or when bi-wired).  But when you feed different sections of the speaker with different amp channels, the proper balance will be maintained only if the amp levels and gain are the same.

So, if you want to consider using a tube amp for the midrange/tweeter sections and solid state for the woofer, the amps will have to have the same gain structure or the relative levels of bass to midrange/tweeter will not be correct.  Again, the crossover is designed to feed appropriate frequencies at the appropriate gain to each of the divers.  If the crossovers are fed signals that are not at the same gain level to begin with, the passive crossovers cannot correct for that.

The bottom line is that you either have to use the same basic amps to drive each of the sections (thus eliminating the tube/solid state combination) or you have to make sure that each of the amps gain structures are the same (which would probably require some mods to one or the other). 

There are other ways to get around this, but those are topics for another post.

I hope this helps.

- Jim