New to seperates and wondering if I can cause damage with these choices? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 5 Old 09-22-2019, 08:38 PM - Thread Starter
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New to seperates and wondering if I can cause damage with these choices?

Firstly, we don't normally blast the volume when watching movies so I don't know how much of a concern this really should be.

So I'm looking at either the Emotiva XPA-11 or pairing an XPA-7 with a 4 for the ceiling atmos. With the way their equipment is expandable maybe I can order and install additional stereo amp modules if I want to bump up the 6 channel atmos? Emotiva only advertises two channels driven for anything above 7 channels so I pulled some numbers out of the air.

Advertised Power Output; chosen models; all channels driven; THD <0.1% ; 8 ohms:
XPA-2 Gen3: 300 watts RMS per channel
XPA-3 Gen3: 275 watts RMS per channel
XPA-4 Gen3: 260 watts RMS per channel
XPA-5 Gen3: 250 watts RMS per channel
XPA-6 Gen3: 225 watts RMS per channel
XPA-7 Gen3: 200 watts RMS per channel

Guessing/pulling these 8 ohm numbers out of who knows where:
XPA-9 Gen3: Mono x5 225 watts RMS per channel / Stereo x4 65 watts RMS per channel
XPA-11 Gen3: Mono x3 250 watts RMS per channel / Stereo x8 50 watts RMS per channel


I have the below Klipsch speakers and wondering if pushing them with the below amps (if the wattage is even necessary and accurate) could cause damage? I understand under normal usage like action movies that the speakers won't normally even see 50-100 watts. Maybe only during explosions or similar tracks but this is the first time I've really dove into researching pre-pro/amp separate setups. I just don't want to spend all this money only to get a surprise fizzle and an electrical burning smell.

Current
Front L/R Klipsch 8000F's (150w RMS/600 peak)
Center Klipsch 504C (150w RMS/600 peak)
Surround L/R Klipsch 600M (100w RMS/400 peak)

650 watts total if running RMS continually, 1600 peak.

Future
Surround Back L/R Klipsch Pro 160-RPW (50w RMS/200 peak)
Atmos x4 Klipsch Pro 160-RPC (50w RMS/200 peak)

adds 300 watts RMS, 1200 peak.

So in a vacuum during a test it would be 950 watts RMS and 2800 watts peak.......am I thinking too much about this?


This kind of rambled on all over the place...hope it made sense

Last edited by mach250; 09-23-2019 at 02:27 AM.
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post #2 of 5 Old 09-22-2019, 09:31 PM
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Quote:
Originally Posted by mach250 View Post
[B]... am I thinking too much about this? ...
Almost. There's one thing you need to add...

Look up your speaker specs for "sensitivity." For example, the 8000's are rated: 98dB @ 2.83V / 1m.
- 98 dB is the SPL
- @ are test conditions
- 2.83v yields 1W @ 8 ohms, and more at lower impedance (power = V^2/R).
- 1m is a 1 meter listening distance, which follows the inverse square law so at 2m, SPL is 1/4 the level.

Now, figure out the SPL at, say, 100W.
- 2x power is +3dB
- 4x the power is +6dB
- 10x power is +10dB
- 100x power is +20dB
- Your 8-ohm 8000's are rated for 118dB @ 100W, 1m
- I sit about 2m away from my speakers, so 100W delivers 112dB from each speaker.

But you have 5 speakers, each with its own amp...
- +3dB for each 2x speaker cone area
- +3dB for each 2x amp power.
- a low estimate (based on 4) speakers is two doublings of each, +12dB

That gives you an SPL well north of 124dB at your seat, from only 100W. You'd make THX with 10W.

Any AVR can deliver 10W/channel, and the only reasonable amp candidates are the XPA-9 and -11. Those speakers don't need a lot of power unless you have a really large space to fill, and then there are better options.

Conversely, if you have 88-90dB sensitivity speakers, you need 100W to tickle THX levels at 2m listening distance from 5 speakers. That's why there's an XPA-5 Gen 2 sitting under my kitchen table.

HAve fun,
Frank
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post #3 of 5 Old 09-23-2019, 12:34 AM
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There is less chance of damage to speakers with powerful amps compared to weak amps. Atmos especially and surround channels dont really use much power at all so no need for big amps for those. The front 3 (LCR) is the place for power if you want/need.
Dont go totally nuts with the volume control and you should be fine, the gear is made to be used.


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post #4 of 5 Old 09-23-2019, 02:25 AM - Thread Starter
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Quote:
Originally Posted by fbov View Post
Almost. There's one thing you need to add...

Look up your speaker specs for "sensitivity." For example, the 8000's are rated: 98dB @ 2.83V / 1m.
- 98 dB is the SPL
- @ are test conditions
- 2.83v yields 1W @ 8 ohms, and more at lower impedance (power = V^2/R).
- 1m is a 1 meter listening distance, which follows the inverse square law so at 2m, SPL is 1/4 the level.

Now, figure out the SPL at, say, 100W.
- 2x power is +3dB
- 4x the power is +6dB
- 10x power is +10dB
- 100x power is +20dB
- Your 8-ohm 8000's are rated for 118dB @ 100W, 1m
- I sit about 2m away from my speakers, so 100W delivers 112dB from each speaker.

But you have 5 speakers, each with its own amp...
- +3dB for each 2x speaker cone area
- +3dB for each 2x amp power.
- a low estimate (based on 4) speakers is two doublings of each, +12dB

That gives you an SPL well north of 124dB at your seat, from only 100W. You'd make THX with 10W.

Any AVR can deliver 10W/channel, and the only reasonable amp candidates are the XPA-9 and -11. Those speakers don't need a lot of power unless you have a really large space to fill, and then there are better options.

Conversely, if you have 88-90dB sensitivity speakers, you need 100W to tickle THX levels at 2m listening distance from 5 speakers. That's why there's an XPA-5 Gen 2 sitting under my kitchen table.

HAve fun,
Frank



Hmm, wondering if I'm going too far into the woods having fun with new toys seeing how my room is only 13'x18'. I might minimize my wants down to just doing a 5.2.4 system and be happy. Might just go with a Denon 4500 to keep it simple...I just end up getting bored at work and shop around.



edit: Maybe just get a 3 channel to push the LCR though...hmm
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post #5 of 5 Old 09-23-2019, 02:29 AM
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New to seperates and wondering if I can cause damage with these choices?

Quote:
Originally Posted by mach250 View Post
Hmm, wondering if I'm going too far into the woods having fun with new toys seeing how my room is only 13'x18'. I might minimize my wants down to just doing a 5.2.4 system and be happy. Might just go with a Denon 4500 to keep it simple...I just end up getting bored at work and shop around.


Haha, ye that can happen
A denon 4500 would be very nice by itself and with options to expand if you want later and cant help yourself.

Edit: a 3 channel could be a good idea but thats easily something that can be done at a later date.
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