JBL Performance Series

[Titanium Dome]

the show predates me, so I didn't know him, the show, let alone what speaker brand he endorsed

stay tuned on a hosted day, it's an issue of almost never having the house w/o the three little ones around, but if the opportunity arises, something I definitely would like to do.....Chicago's Best is right down the street and they sell in bulk the authentic Vienna Beef, hot giardiniera, rolls, and au jus to make a real Chicago beef sandwich, which is unlike any other in any city anywhere as you prolly know

Would love some Vienna Beef. I stopped at Downtown Dog when I was at a conference in Chicago last month. MMMMMmmmmmm.

Oh, and love to hear the system, too.

You can see Richard Boone (Paladin: Have Gun Will Travel) admiring JBL products right on this site:

http://www.audioheritage.org/html/forums/forums.htm

[JBLAddict]

I use a couple of these for all purpose stands.

http://www.amazon.com/Sanus-Steel-Fo...6110383&sr=8-5

Very heavy and they have a extra large top plate that will support much larger speakers than the PT800. They are not cheap in pairs. Can be filled with sand or shot, come with spikes and rubber pads.

got it worked out. I used two old bookshelf speaker stands, attaching the two bases to one support post, making it wide enough on top to hold the PT. Even without being bolted down, the PT is surprisingly stable, though this weekend I will drill some new holes to attach to the bottom plate.

I was in the middle of attaching the standard small top pedestal and my wife said "why don't you just put the two bases together" so once again my "better half" proved better

[JBLAddict]

I'm not understanding how the PT/PS stack creates even/proper power distribution to the two units?

I'm looking at it as a bi-amped speaker, where the LF is getting all 400W and the MF/HF is getting only the power of the amplified input signal.

Does this imply I need the input signal amplified to 400W for the stack to be balanced the same as a standard speaker with a single amplified input?

[rdgrimes]

I'm not understanding how the PT/PS stack creates even/proper power distribution to the two units?

I'm looking at it as a bi-amped speaker, where the LF is getting all 400W and the MF/HF is getting only the power of the amplified input signal.

Does this imply I need the input signal amplified to 400W for the stack to be balanced the same as a standard speaker with a single amplified input?

Not at all. The sound below 130Hz normally draws around 90% of the available power in any speaker. Even in an active bi-amp setup with any speaker, you don't need to apply equal power to each channel.

I can't even imagine the levels generated if you were to drive these units high enough to justify 400W continuous into the PT800. That said, I have to admit that I do have 400WPC available into 5 of my PT800. But the difference between 400 and 200 is only VERY slightly audible and only at painful levels.

I'd have to say that even 100WPC will drive the PT800 very nicely to levels well beyond normal. By that I mean a true 100WPC, not an AVR rated at 100WPC.

[grumpy]

It might help to think of amps as voltage gain stages;
with some having a higher output voltage limit (above
which, the amplifier clips). If the amplifiers have the
same sensitivity (or are adjusted at their inputs to be so),
then the same input level to each amp will result in
matching output voltages. If you apply the outputs to
a load, such as a speaker, the resulting dissipation in
watts will also be the same for both amps (assuming
identical speakers). With different speakers, they have
their own impedance vs frequency and sensitivity, so
biamp level matching can require further adjustments
beyond amp sensitivity (or one can trade off sensitivities
in each area). So... 'watts', as used to specify an amp
in the audio biz, is more an ultimate capability, sort of
like hp and torque specs for a car. I've intentionally
simplified things a bit, but I hope that helps

[rdgrimes]

Also good to note that the PS1400 has a level control specifically for the LF input. If you're doing spectrum analysis and EQ, this can be used to influence response curves. I'd suggest starting with that level control set at "0". Small changes can have a big effect depending on the source. And to further complicate things, if you use the LFE input and have the stacks on a 80Hz XO in your processor, you can use both the LF and LFE level adjustments to tweak the <80Hz and 80-130Hz bands separately. Are we having fun yet?

[JBLAddict]

It might help.... I've intentionally
simplified things a bit, but I hope that helps

Not at all.
I'd have to say that even 100WPC will drive the PT800 very nicely to levels well beyond normal. By that I mean a true 100WPC, not an AVR rated at 100WPC.

Thanks guys for the excellent explanations. That clarifies one key question on the stack.

WRT to the full 5.1 ... the situation is that I'm back to using my HK 75WPC AVR354 for the 5.0 channels, and the convenience of using the AVR for all functions is very nice, and I'd like to keep it that way if it's not a substantial sonic compromise. I figured with a 91dB PT800 only driving above 130Hz the fronts, in particular, would be fine this way, as would the surrounds and center above 80Hz

It sounds fine enough for 2CH music, as well as movies and MCH music, but I still have the "use the maximum recommended amplified power for adequate headroom for occasional peaks" from the user manual on the brain.

I had the L7s on a separate amp for obvious reasons but am really hoping the PT/PS stack allows me to recapture the convenience of an AVR w/o real compromise

[JBLAddict]

The bottom plate of the PT800 can be removed and fixed to just about any stand capable of supporting it. The PT800 plate will lay flush on any flat surface. So it's really just a matter of getting a stand of the correct height with a flat plate big enough for the PT800. If the top plate on the stand is larger than the footprint of the PT800, you could also just bolt the speaker directly to that. They are standard sized machine screws that go into the speaker.

Took a better look at it. Unless I'm missing something, it seems without a gap below the PT800 there isn't a way to mount the PT-plate to the stand, and the PT to the plate without using an extra long bolt through the top plate of the stand? Same as if I was to bolt the speaker to top of the stand directly, bypassing the PT plate altogether.

[grumpy]

If times and logistics ever work out, remind me and I'll bring 5ch of 150w (Proceed)
that you can compare and judge for yourself (will need 5 rca cables). I'd think you
would be quite happy with the AVR, but I understand that it's somehow more
comforting when you are able to prove it to yourself (or at least can understand
the incremental nature of such an upgrade and can gauge it's relative importance to
you at this time vs ... pretty much anything else)

[Don C]

You do need to leave yourself a way to fasten the plate to the speaker, after you have mounted the plate to the stand. One might be able to just use the metal plate as a pattern to drill eight holes in the top of the speaker stand. Four to fasten the stand to the plate, then four more larger ones to put the screws in from below to fasten the plate to the speaker. You have to figure it out based on what stands you are using, but it can be done. If the top part of your speaker stands are small, you might have to drill four new holes in the plate to match the size of the stand. Bolting all the way through the stand and the existing holes in the speaker cabinet would be fine too, just use the metal plate as a pattern to drill, and you'll need longer screws.

[JBLAddict]

You do need to leave yourself a way to fasten the plate to the speaker, after you have mounted the plate to the stand. One might be able to just use the metal plate as a pattern to drill eight holes in the top of the speaker stand. Four to fasten the stand to the plate, then four more larger ones to put the screws in from below to fasten the plate to the speaker. You have to figure it out based on what stands you are using, but it can be done. If the top part of your speaker stands are small, you might have to drill four new holes in the plate to match the size of the stand. Bolting all the way through the stand and the existing holes in the speaker cabinet would be fine too, just use the metal plate as a pattern to drill, and you'll need longer screws.

good ideas thanks. thinking a longer bolt of the same size through the stand top-plate is cleanest option....though I was really hoping for a solution with the hardware I have and not have to visit the hardware store

[JBLAddict]

If times and logistics ever work out, remind me and I'll bring 5ch of 150w (Proceed)
that you can compare and judge for yourself (will need 5 rca cables). I'd think you
would be quite happy with the AVR, but I understand that it's somehow more
comforting when you are able to prove it to yourself (or at least can understand
the incremental nature of such an upgrade and can gauge it's relative importance to
you at this time vs ... pretty much anything else)

I hear ya, would be good to try. Overall, was hoping the >80Hz nature of the satellite PTs would negate the need for high power to satisfy typical headroom issues of a full range unit....seeing that 90% of the power goes to <130Hz as stated.

[Mr. Widget]

I hear ya, would be good to try. Overall, was hoping the >80Hz nature of the satellite PTs would negate the need for high power to satisfy typical headroom issues of a full range unit....seeing that 90% of the power goes to <130Hz as stated.

As was eluded to above... I wouldn't be as concerned by the amount of watts as the quality of them and the quality of your preamp. These speakers deserve a high quality set of electronics... but that can come along later.


Widget

[JBLAddict]

These speakers deserve a high quality set of electronics... but that can come along later.

Widget

well said, deserved, and over time

If the top plate on the stand is larger than the footprint of the PT800, you could also just bolt the speaker directly to that. They are standard sized machine screws that go into the speaker.

Done, had a bunch of 1 3/4" long screws of the same diameter, the exact length needed to compensate for the 1/2" of the stand topplate and 1/4" recess on the bottom of the PT....drilled holes in the stand turned everything upside down and bolted together.

[rdgrimes]

well said, deserved, and over time



Done, had a bunch of 1 3/4" long screws of the same diameter, the exact length needed to compensate for the 1/2" of the stand topplate and 1/4" recess on the bottom of the PT....drilled holes in the stand turned everything upside down and bolted together.

Whatever works. Look at the stacks - the surface that meets the pillars from the PS1400 is more or less flush with the bottom edge of the PT800 cab. Those 4 holes can be used to attach to any flat plate.

I hear ya, would be good to try. Overall, was hoping the >80Hz nature of the satellite PTs would negate the need for high power to satisfy typical headroom issues of a full range unit....seeing that 90% of the power goes to <130Hz as stated.

Yes, but you're only talking about transients here, and the amp's ability to control the drivers at higher levels. You CAN hear differences between 100W, 200W and 400W, but those differences diminish proportionally. The bigger (and better) the amp, the better it can deliver those transients and still maintain the smaller details. High resolution audio like SACD and DVD-A made from quality masters is the real test.

I'd say the PT800 is just as likely to deliver more pleasing sound with higher power as the L7 is.