Line Level vs Speaker Level?

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PLMONROE

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Line Level vs Speaker Level?
« on: 17 Feb 2007, 09:55 pm »
Hopefully by this time next month I should have my RM-V60 so I am trying to line up my ducks. My understanding is that the plate amp on the subs accepts both line level and speaker level inputs. Now I have another *^%$#&)&^##% choice to make! For equal run lengths will I get better sound using one type of input over the other?  :scratch: :scratch: :scratch:

Brian Cheney

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Re: Line Level vs Speaker Level?
« Reply #1 on: 17 Feb 2007, 10:45 pm »
The amp has line level inputs only.

Housteau

Re: Line Level vs Speaker Level?
« Reply #2 on: 18 Feb 2007, 12:03 am »
When setting up stereo subs using the PBS, should both the L & R inputs on each amp be supplied together using a Y-cable?  It seems I remember reading something about that and certain plate amps.

Brian Cheney

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Re: Line Level vs Speaker Level?
« Reply #3 on: 18 Feb 2007, 01:43 am »
The plate amps are set up with two (L and R) inputs, either of which will drive the amp.  So you do not have to mono out the signal, the amp will do it for you.

avahifi

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Re: Line Level vs Speaker Level?
« Reply #4 on: 18 Feb 2007, 01:50 am »
If I am not intruding, I would suggest line level rather than speaker level to drive a subwoofer.  This way the signal is not further modified by the main power amplifier.  Speaker level essentially puts two amplifiers in series before the signal gets to the woofer itself, first the main amp and then the woofer amplifier. 

All other things being equal, I think line level will provide the most accurate results.

Regards,

Frank Van Alstine

Brian Cheney

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Re: Line Level vs Speaker Level?
« Reply #5 on: 18 Feb 2007, 01:52 am »
No argument with you there, Frank.  Feel free to post on my forum anytime.

warnerwh

Re: Line Level vs Speaker Level?
« Reply #6 on: 18 Feb 2007, 06:41 am »
These plate amps have L and R as well as a LFE input. That's the one you want to use and is the one I use on my sub even though it's only the right channel sub. No need for Y cables on these amps. If you use a single L or R input the amplifier will not be able to use it's entire output capability.

I'm pretty sure your speakers will sound much better if you have them sent to Portland first. Being the nice guy I am I'll pay half of shipping for you. I can dial them in for you better than anyone else in the world. After about a year you'll be so pleased with the sound you'll probably want me to have them as a gift. :thumb: In which case I'd feel obligated to give you a very nice pair of RM 40's. Let me know how you'd like me to send my Rm 40's to you. If you live within a thousand miles I'll deliver them. aa

Housteau

Re: Line Level vs Speaker Level?
« Reply #7 on: 18 Feb 2007, 07:11 am »
I see that there is a link for the manual:  http://www.partsexpress.com/pdf/300-808.pdf

According to it, a Y-cable for the L & R is needed to drive the amp to full output.  It also explains why the LFE would not be the way to go in a passive system:

Left/Right Inputs:
 
RCA style jacks that will accept standard line level inputs from a pre-amp level source. They will
accept a stereo signal and internally combine it into mono. Both left and right input jacks must
be connected to the source in order to drive the amplifier to full output. The use of a “Y” cord is
suggested if a mono source is all that is available.


LFE Direct Input:

RCA jack that will accept a signal from the mono LFE (Low Frequency Effects) output on a preamp
or receiver that is equipped with a dedicated sub bass output. This input bypasses the
amplifier’s own internal low pass filter circuitry, relying instead on the processed output
provided by the source equipment. This would be the recommended connection for most home
theatre surround sound receivers and pre-amps. We would also suggest the use of the LFE
input when an external line level electronic crossover or frequency dividing network is used.

warnerwh

Re: Line Level vs Speaker Level?
« Reply #8 on: 18 Feb 2007, 07:20 am »
Good point Hosteau. I forgot I'm using an active crossover as my other sub is driven by a spare channel of a 3 channel amp so I use the active crossover before the plate amp also allowing me to use the LFE input.  My error on that point. You do need to use both inputs though for full power. I'm very impressed with this amp. If it lasts for years I'll really be pleased as I used to think plate amps weren't worth the effort. The last plate amp I used worked well too but these HPSA plate amps from PE are as good as a quality power amp.

PLMONROE

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Re: Line Level vs Speaker Level?
« Reply #9 on: 18 Feb 2007, 04:20 pm »
I see that there is a link for the manual:  http://www.partsexpress.com/pdf/300-808.pdf



Left/Right Inputs:
 
RCA style jacks that will accept standard line level inputs from a pre-amp level source. They will
accept a stereo signal and internally combine it into mono. Both left and right input jacks must
be connected to the source in order to drive the amplifier to full output. The use of a “Y” cord is
suggested if a mono source is all that is available.


LFE Direct Input:

RCA jack that will accept a signal from the mono LFE (Low Frequency Effects) output on a preamp
or receiver that is equipped with a dedicated sub bass output. This input bypasses the
amplifier’s own internal low pass filter circuitry, relying instead on the processed output
provided by the source equipment. This would be the recommended connection for most home
theatre surround sound receivers and pre-amps. We would also suggest the use of the LFE
input when an external line level electronic crossover or frequency dividing network is used.

Am I to understand from this that I could run my 2 channel audio to the plate amps through a Y connector to the L & R inputs AND run the LFE output from my  separate Home Theater system to the LFE jack on the same amps as well? If so, I could then also use these awsome speakers as my home theater subs. :drool:

Paul

John Casler

Re: Line Level vs Speaker Level?
« Reply #10 on: 18 Feb 2007, 07:09 pm »
Am I to understand from this that I could run my 2 channel audio to the plate amps through a Y connector to the L & R inputs AND run the LFE output from my  separate Home Theater system to the LFE jack on the same amps as well? If so, I could then also use these awsome speakers as my home theater subs. :drool:

Paul

I know that is possible with the NHT X-2 crossover that I use (which gives me 5 subs for my HT) but I have not heard a report about the SUB amps having that same capability.

It would seem possible, but one might wonder how it would "separate" and isolate the signals, if you don't do it in the system before hand.

That is, if you run the L&R ins off the Preamp for 2 channel, and then the LFE off the Pre/Pro, then it would seem that when running HT, "BOTH" would be sending signal at the same time using different x-over points.

It may have some kind of sensing, or maybe it won't create a problem, but the literature doesn't seem to address it, and I haven't heard of anyone doing it.

It would be nice if it did, but you would still need to work out the two different "x-over" points. (although with the RM v60 the x-over is 70Hz and with HT the "general" point is 80Hz)


PLMONROE

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Re: Line Level vs Speaker Level?
« Reply #11 on: 18 Feb 2007, 07:56 pm »
I see that there is a link for the manual:  http://www.partsexpress.com/pdf/300-808.pdf




LFE Direct Input:

RCA jack that will accept a signal from the mono LFE (Low Frequency Effects) output on a preamp
or receiver that is equipped with a dedicated sub bass output. This input bypasses the
amplifier’s own internal low pass filter circuitry, relying instead on the processed output

Thanks John, I am not sure myself. Currently I  use the Krell Home Theater Standard Processor for my Home Theater. It has a LFE output crossing over at 80hz. My current preamp for my music system is a Sonic Frontier SE2 (soon to be the Ambrosia).  aa  If the above excerpt is correct, it would indicate to me that an input from the Krell to the LFE would bypass the 70hz crossover seen by the L & R RCA jacks. Since both systems would never be playing at the same time (or even powered up at the same time for that matter) perhaps the only concern might be ground loops which shouldn't be too  difficult to resolve. However this is way above my head and I may be well overlooking all sorts of things, hence this post.