LSi25 Sub Amp Clipping Prevention

T-Liner4Life

Hi,

I've just purchased a new set of LSi-25's and I was showing a friend a blu-ray to demo the sound and I thought I noticed that the subs in the 25's were clipping, but not sure. I just know for sure it sounded bad, so I quickly turned the volume down on them. My question is, how do you know if the subs are clipping (other than with your ear), and is there a good/recommended configuration to avoid it?

Currently I'm just using an Onkyo 805 to power them and them only. Also, I am only using the high level speaker input with the straps in place. I haven't tried the line level inputs yet and removing the straps. I do plan in the near future to use a separate amp to power these as I can already see my Onkyo is having a hard time driving them.

Any advice is greatly appreciated. Thanks.

slk55amg

You could damage the receiver and the speakers trying to drive them with a receiver alone, You need an amp(quickly)

T-Liner4Life

As long as I keep the volume at pretty moderate levels I should be ok right? My avr is only driving these 2 speakers and nothing else. I thought if I didn't turn the volume past +0db I wouldn't be hurting anything b/c my receiver amp wouldn't be distorting. As it is I have found a need to turn the knob much past -20db.

I've been looking at a Russound x225 amp, what are your thoughts on that? Thanks for your help.

slk55amg

I don,t know anything about that amp. I am driving my LSI15, LSIC and side surrounds with an EMOTIVA XPA5 and its terrific.

slk55amg

You " should " be ok, it would make me nervous, my receiver a SONY ES5300 is rated for 4ohms, I bought the amp first, not wanting to take a chance on damage to my avr or speakers.

mantis

Set the Lsi25's in small and run LFE to each speaker over Line level RCA. Then calibrate system , do one sub at a time.
Steps to setup the lsi25's.
1) Speaker wire for high and mids
2) RCA sub wire for LFE
3) Use a Y splitter if your receiver doesn't have 2 sub outs
4) unplug one sub and calibrate entire system
5) unplug other sub and plug in sub not calibrated and recalibrate
6) Now plug both subs together and calibrate together which will give you equal bass from both subs.
Your calibration should be done at 0db out from test tone , 75db on your meter and use the volume knob on the subs each to get the correct level , once this is achieved then both can be calibrated line leve and you use the receiver to adjust the volume of both subs.

This should prevent any clipping in the future.
6

T-Liner4Life

Thanks for the advice,

but I feel like an idiot. I guess i've never calibrated anything before because I didn't understand half of what you said. My experience with setting up speakers is to plug the little microphone into the avr and let it do its thing. Any chance I could ask you to be more descriptive on how to calibrate the subs?, or maybe recommend a book/source i could research to gain some knowledge. Thanks.

JimAckley

+1 on what Mantis said. Running them through LFE is by far the easiest way to drive them sans amplifier.

Even taking off the jumpers and running the L/R line-outs to your 25s' subs will help a great deal. When I first bought mine, I had a lot of difficulty powering them with my AVR. Then I opted for using line-level connections via my receiver's LFE out, which also enabled the crossover (100Hz is a pretty good point for those speakers), and only went into protection at the highest volumes.

In short, you'll need an SPL meter. Measuer your left sub's volume with the right sub amp turned off. Then turn off the left amp and meter the right sub. Get them set to the same volume on the SPL meter. Now make sure both amps are on, and fine tune the subwoofer leve in your receiver's speaker-level settings.