Bi amping? is 8watts enough?

[theluggman]

I have a pair of Khorns with a Bryston 4B will a tube amp of 8 watts be enough for the tweeter and mid??

[russ69]

It would be for me but I don't crank it up that much. Someone will come along and explain the math but for me the whole reason to bi-amp is to get more punch. If you want punch, that takes some power. So I guess my queston is why do you need to bi-amp?

[Islander]

It might be enough for the tweeters alone, but not for the squawkers.

The power needs of the drivers vary, depending on where they're crossed over. The more octaves of the audio band that the driver is asked to cover, the more power is needed. With a bi-amped 2-way speaker, if the crossover point is around is around 470-500Hz, that represents the five lower octaves for the woofer and the five higher octaves for the tweeter, so the woofer and tweeter need roughly equal amounts of power. This is why Jubilee and JubScala owners usually use matching power amps for bass and treble.

Also, more punch is not the only reason to bi-amp. Distortion is reduced when the amp is only reproducing part of the audio band.

True bi-amping with an electronic crossover can also make it easy to time-align the drivers.

[djk]

Does your tube amp have a 16R tap?

The K55 is attenuated down to 104dB/2.83V/1M in the network. If you hook it to the 16R tap on a tube amplifier it will be 110dB/W/1M. 8W is 9dBW, so it will play 119dB by itself. The bass will add another 6dB to the aggregate SPL, or 125dB. Add another 3dB for the other speaker (assuming stereo).

Do you need it to play louder than 128dB peak?

The tweeter crossover will be the one from the Klipsch LB-76, it boosts the drive to the tweeter by 6dB to match the K55.

[russ69]

Also, more punch is not the only reason to bi-amp. Distortion is reduced when the amp is only reproducing part of the audio band.

I'm not sure how you measure that?

[Islander]

Also, more punch is not the only reason to bi-amp. Distortion is reduced when the amp is only reproducing part of the audio band.

I'm not sure how you measure that?

Err, with your ears? Actually, if the treble amp is not reproducing anything below the crossover point, it won't be producing any harmonics from that part of the audio band, so that makes for clearer/cleaner sound.

[russ69]

Is it measurable? Just curious?

[jacksonbart]

Is it measurable? Just curious?

is fancy cable?

[russ69]

is fancy cable?

Good point jackson, but I've never properly bi-amped with an external crossover so I don't have any experience with it, although I have played with my brother's tri-amped rig but not enough to be real knowlegable.

Thanx, Russ

[Islander]

Is it measurable? Just curious?

I'd think it would be measurable, but one of our engineers on the forum would know a lot better. In my case, I just followed the recipe, and in going from 3-way to 2-way, passive crossover to active, exponential mid and high horns to modified Tractrix, old mid driver to new large format mid/high driver, single amp to bi-amping, improved EQ settings, plus time-aligning the drivers, it's hard to point at one single thing that made the sound so much better.

I can just say that the whole package really works! Everyone who's heard the system comments on the amazing clarity and lack of distortion at all volume levels, along with the lifelike dynamics.

To get back to our original poster, his Bryston 4B amp puts out 250 Wpc or more, depending on the series (original, ST, or SST), which would be hard to match with an 8-watt tube amp for the treble.

[djk]

"which would be hard to match with an 8-watt tube amp for the treble."

What part of 128dB didn't you understand?

[Sandy West]

The improvement in distortion is measurable. Intermodulation distortion is greatly reduced, almost to zero, as each amplifier is handling different parts of the frequency spectrum.

[kevinmi]

I bi-amp my Khorns with a 60wpc tube amp on the lows, and two 5.5w SET monoblocks for the mids/highs. There is more than enough power for me with this setup. I am, however, running different drivers/horns for the mids/highs. Try it, I think you will be pleasantly suprised!

[russ69]

I can just say that the whole package really works! Everyone who's heard the system comments on the amazing clarity and lack of distortion at all volume levels, along with the lifelike dynamics.

I have no doubt, that your system is, as jacksonbart says, topnotch!

[theluggman]

I bi-amp my Khorns with a 60wpc tube amp on the lows, and two 5.5w SET monoblocks for the mids/highs. There is more than enough power for me with this setup. I am, however, running different drivers/horns for the mids/highs. Try it, I think you will be pleasantly suprised!

Can I ask you are you running an electronic or passive crossover and if electronic which one? Thanks for your input, I am excited about this project but apprehensive on how much is my sickness gonna cost me!

[Ski Bum]

The improvement in distortion is measurable. Intermodulation distortion is greatly reduced, almost to zero, as each amplifier is handling different parts of the frequency spectrum.

I would also imagine that in a properly bi- or tri-amped system, with amps connected directly to drivers w/o any passive crossover components would yield easily quantifiable results. A raw driver is a way friendlier, flatter load than said driver coupled with phase shifting, impedance-fluctuating passive crossover parts. Fully actice makes sense no matter how you look at it.

To the OP's original question, I use 300w/chan paired w/ approx 6 watts for the top end, and it works great within it's limits. I just don't crank it like a teenager that much any more. It's still good to over 100db at my chair before running out of steam, which is still bowl-you-over loud, and more than I can tolerate for more than brief sessions.

[theluggman]

The improvement in distortion is measurable. Intermodulation distortion is greatly reduced, almost to zero, as each amplifier is handling different parts of the frequency spectrum.

I would also imagine that in a properly bi- or tri-amped system, with amps connected directly to drivers w/o any passive crossover components would yield easily quantifiable results. A raw driver is a way friendlier, flatter load than said driver coupled with phase shifting, impedance-fluctuating passive crossover parts. Fully actice makes sense no matter how you look at it.

To the OP's original question, I use 300w/chan paired w/ approx 6 watts for the top end, and it works great within it's limits. I just don't crank it like a teenager that much any more. It's still good to over 100db at my chair before running out of steam, which is still bowl-you-over loud, and more than I can tolerate for more than brief sessions.

Thanks for your reply I am intrigued, which crossover are you using, I am have a difficult time; a) finding one finding any opinoins about them

[Ski Bum]

Thanks for your reply I am intrigued, which crossover are you using, I am have a difficult time; a) finding one finding any opinoins about them

Ah, unfortunately I'm stuck in the passive-crossover dark ages, simply passive bi-amping for now. Even with the power robbing passive parts in place, the 6 watts gets plenty loud (for my old ears, at least), and seems to work well in spite of the limitations. I'm almost afraid to go active, because then I'll get hooked and have to do it for all four sytems in the house, and that would be a huge PIA! The only active system I've had extensive experience with was fantastic, and the crossovers were integral to the speakers (M&K active monitors, and a pro-audio looking bass management unit).

Search the forums for 'active crossover' and you'll get many suggestions. Most will be pro-sumer type gear widely available at your local musician/pro audio store, and for less cost than you might expect. Other forum members are far more knowledgable than myself, and some of these guys have tremendous experience setting up their Klipsch as active speakers. You're in the right place.

[Islander]

People have had good results with the Electro-Voice Dx38, the Electro-Voice DC-One, the Yamaha SP2060. Those ones have been mentioned on this forum, plus there are other good ones out there.

[kevinmi]

I usually run a passive "Universal" type of crossover with this setup. Right now I am trying a Behringer DCX2496 active crossover that is on loan to me. The active crossover is amazing as far as all the adjustments available, but you have to have 6 channels of amplification (3 stereo amps in my case) plus 3 runs of speaker cable to your speakers. It is definately going to be more expensive!