# Crown XLS 2502 - Defective?

#### Chrispy

##### Master Contributor
Forum Donor
Thanks, I think some of the posters were assuming I was pushing that much power through speakers. So maybe it is a good idea to keep the bridge after all. You say dual 4 ohm? I thought it was dual 2 ohm. I do have them wired in series.
I was more wondering why you thought you needed such power. For sealed subs perhaps due the usual eq demands.

#### Thomas_A

##### Major Contributor
Forum Donor
You should calculate it in SPL (sound pressure level) terms...

A speaker efficiency is usually quoted in terms of SPL per Watt at 1m (or SPL per 2.83V at 1m - 2.83V at 8ohm is 1W) - and in db

For each doubling of distance the SPL will reduce by 3db

So if your target is 110db - and your listening point is 4m from the speaker you would need 110db + 3db (@ 2m) +3db (@4m) - for a total of 116db at 1m - that would be the output from the speaker needed for 110db at the MLP (main listening position)

a speaker will put out an additional 3db for each doubling of power...

So if its efficiency is 90db SPL / Wm - then output will be:

90db @ 1W
93db @ 2W
96db @ 4W
99db @ 8 W
102db @ 16W
105db @ 32W
108db @ 64W
111db @ 128W
114db @ 256W
117db @ 512W

If you have 2 speakers with the same specs - the sum of the two will add 3db (doubling of power!)

So if you know the efficiency of the speaker - and you know the desired loudness (sound pressure level) - you can calculate your power requirements.

The speaker specifications in terms of power handling are a specification of how much power can be pushed through the speaker before it starts to melt down, or tear itself apart.... - you can pretty much ignore it in other words!!
For a sub placed near wall, you can add both boundary gain and room gain. Plus you could eq peaks down to get more even response and gain power.

D

#### Deleted member 48726

##### Guest
I was more wondering why you thought you needed such power. For sealed subs perhaps due the usual eq demands.
Can't really have too much power. Maybe OP got a good deal on the amp? He writes in no 10 that he bought it in case he needed another sub later on. Which power wise sounds alright.

#### Chrispy

##### Master Contributor
Forum Donor
Can't really have too much power. Maybe OP got a good deal on the amp? He writes in no 10 that he bought it in case he needed another sub later on. Which power wise sounds alright.
You're not really gaining power otoh. Just shifting it a bit.

D

#### Deleted member 48726

##### Guest
You're not really gaining power otoh. Just shifting it a bit.
Huh?

#### middlemarch

##### Active Member
Forum Donor
I have that same Crown amp, driving that same Dayton sub in a sealed box with one of the two channels, the other channel driving a second sub with dual 12" drivers. The dual is 4 ohms, the Dayton has both coils in series, so 4 ohms. I have driven the system to as loud as I ever want to go. The Crown has LEDs that light when the -20dB (of full scale) point is reached. Neither LED has ever come on. Bridging that amp in the above application would be insane overkill.

#### dlaloum

##### Major Contributor
I have that same Crown amp, driving that same Dayton sub in a sealed box with one of the two channels, the other channel driving a second sub with dual 12" drivers. The dual is 4 ohms, the Dayton has both coils in series, so 4 ohms. I have driven the system to as loud as I ever want to go. The Crown has LEDs that light when the -20dB (of full scale) point is reached. Neither LED has ever come on. Bridging that amp in the above application would be insane overkill.
That is my experience too - never seen the top two led's come on - and barely seen the third one flicker, when I'm being a bit crazy.

People focus too much on "power"!

Forum Donor
Eh?

#### Chrispy

##### Master Contributor
Forum Donor
Just that bridging the amp has limitations, and you are just somewhat shifting the capability range so to speak.

#### sailor2005

##### Active Member
My amp came in what looked like new condition. I am keeping it in the garage for now because my wife isn't letting me bring it into the house... I guess some dust I kicked up today must have gotten into it. At least I hope that's all it was.
The first thing you have to check is the DSP settings on the amp. If you bought it 2nd hand you should have reset it to default and then put your own settings.

#### dlaloum

##### Major Contributor
The first thing you have to check is the DSP settings on the amp. If you bought it 2nd hand you should have reset it to default and then put your own settings.
Yes - the dsp should be checked, but no, that would not show the symptoms described (RCA having issues, XLR working fine)

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