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Title: Do I simply need a bigger amp or bridge the one I have?
Post by: Debbie Dunkley on June 03, 2013, 08:48:29 PM
Your thoughts please Sirs....
I ran sound outside for a couple of bands at the weekend and it sounded fantastic. I had so many great comments and I was really happy with the sound. I had great separation of all the instruments and vocals, the bass was thumping and the bands were really happy with what I was able to do for them. I use 2 x SRX715's bi-amped and 2 x SRX718's. DBX DRPA sets my crossover settings so I do not use DSP in the amps. Simple and clean. I used the same amp set - up I have used in bars and clubs - 2 x Crown XLS 2000's bridged (1300 w/8ohms)per side for the subs, Crown XTI4002 stereo (650w/8ohms) for the mids and an older but very reliable Carvin HT760 for the horns (175w 8 ohms). All the amps were firing really well until about 3/4 way through the night when I assume I had crept up the volume a little bit. I heard no distortion at all and the amps were not hot but I was getting a slight clipping on the left side of the XTI4002 ( not sure why only on one side as I was running the system in mono panned center). I realize that the mid portion of the system is the least powered area (amp 650w - speakers 800w) but I have always had great results so never bothered to change anything. However, now I am thinking maybe I should. Is this simply a case of the amp not producing enough power in stereo? If I bridge the amp, it will send 3200w to the mids - 1600 per side which is quite a bit more than the 650w I have now. Do I bridge (which I don't like doing into 4 ohms) or do I re-think how I am configured right now?? I also own  XLI3500 which I take as my spare.
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Geoff Doane on June 03, 2013, 09:17:15 PM
Your thoughts please Sirs....
I ran sound outside for a couple of bands at the weekend and it sounded fantastic. I had so many great comments and I was really happy with the sound. I had great separation of all the instruments and vocals, the bass was thumping and the bands were really happy with what I was able to do for them. I use 2 x SRX715's bi-amped and 2 x SRX718's. DBX DRPA sets my crossover settings so I do not use DSP in the amps. Simple and clean. I used the same amp set - up I have used in bars and clubs - 2 x Crown XLS 2000's bridged (1300 w/8ohms)per side for the subs, Crown XTI4002 stereo (650w/8ohms) for the mids and an older but very reliable Carvin HT760 for the horns (175w 8 ohms). All the amps were firing really well until about 3/4 way through the night when I assume I had crept up the volume a little bit. I heard no distortion at all and the amps were not hot but I was getting a slight clipping on the left side of the XTI4002 ( not sure why only on one side as I was running the system in mono panned center). I realize that the mid portion of the system is the least powered area (amp 650w - speakers 800w) but I have always had great results so never bothered to change anything. However, now I am thinking maybe I should. Is this simply a case of the amp not producing enough power in stereo? If I bridge the amp, it will send 3200w to the mids - 1600 per side which is quite a bit more than the 650w I have now. Do I bridge (which I don't like doing into 4 ohms) or do I re-think how I am configured right now?? I also own  XLI3500 which I take as my spare.

You sound like you have a pretty good handle on things, so I would be inclined to say go ahead and try it.  Reduce the gain on the XTI4002 by 6 dB to make up for the fact that you're bridging it (unless the setup in the DSP does that already, I don't remember), and the system should behave exactly as it did before, you'll just have more gas available for the 15s, if you need it.

If I was giving the system to someone else to drive, I would feel safer running things the way you had it set up before.  But for live music that isn't compressed to death, 1600 available watts doesn't sound unreasonable for those cabinets.  Running 4Ω bridged is no different than 2Ω stereo, and since it's only the mids, not subs, and you're not likely to run it right to the wall, I think you should be OK.  A friend of mine ran a pair of XTI4000s (the originals) bridged into some 4Ω subs for a couple years, and didn't blow up either the speakers or the amps, so the "improved" amp should be fine.

GTD
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Debbie Dunkley on June 03, 2013, 09:29:37 PM
Your thoughts please Sirs....
I ran sound outside for a couple of bands at the weekend and it sounded fantastic. I had so many great comments and I was really happy with the sound. I had great separation of all the instruments and vocals, the bass was thumping and the bands were really happy with what I was able to do for them. I use 2 x SRX715's bi-amped and 2 x SRX718's. DBX DRPA sets my crossover settings so I do not use DSP in the amps. Simple and clean. I used the same amp set - up I have used in bars and clubs - 2 x Crown XLS 2000's bridged (1300 w/8ohms)per side for the subs, Crown XTI4002 stereo (650w/8ohms) for the mids and an older but very reliable Carvin HT760 for the horns (175w 8 ohms). All the amps were firing really well until about 3/4 way through the night when I assume I had crept up the volume a little bit. I heard no distortion at all and the amps were not hot but I was getting a slight clipping on the left side of the XTI4002 ( not sure why only on one side as I was running the system in mono panned center). I realize that the mid portion of the system is the least powered area (amp 650w - speakers 800w) but I have always had great results so never bothered to change anything. However, now I am thinking maybe I should. Is this simply a case of the amp not producing enough power in stereo? If I bridge the amp, it will send 3200w to the mids - 1600 per side which is quite a bit more than the 650w I have now. Do I bridge (which I don't like doing into 4 ohms) or do I re-think how I am configured right now?? I also own  XLI3500 which I take as my spare.
Thank you so much sir for your response. I will definitely try the amp bridged based on your comments. I will be the only one running the PA and I am VERY careful -especially 'playing' with this much money-and it's MY money LOL!!! I have tried to avoid bridging because of the extra load on the amp (especially the subs) but as the XTI is rated as safe at 4 ohms bridged and as you mentioned it will only be feeding the mids, it has to be worth a try.....I am excited to have a little more headroom next gig....
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: FonsyFernandez on January 21, 2019, 05:30:47 AM
I agree with you, I use a CROWN (http://musicaldcm.es/595_crown) XLI2500 and the times I have used it have been impressive the result of the sound.
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Chris Grimshaw on January 21, 2019, 06:12:05 AM
Not sure I'd bother bridging.

Negatives:
- Running the amp at 2ohm/ch usually increases distortion and operating temperatures compared to 4 or 8ohm use. Safe at 4ohm bridged is not the same as happy at 4ohm bridged.
- You either lose stereo capability, or bring more amps to the gig.

Occasional clipping of that amp on those speakers won't destroy anything, and if it's in a multi-amped setup, most people probably won't notice that the clipping is even happening until it's pretty severe.

Chris
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Keith Broughton on January 21, 2019, 06:33:40 AM
Quote
but I have always had great results so never bothered to change anything
I think that says it all. If it 'ain't broke...
The question to answer first is why was one amp showing a clip indication and the other not.
Find that out and proceed from there.
While it is nice to have more power...with more power comes a greater responsibility...to your drivers ;)
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Debbie Dunkley on January 21, 2019, 08:50:15 AM
Guys, this is a 5-1/2 year old post - MY post -LOL.  I don't even own this stuff anymore. Thanks for the comments anyway though!!
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: David Allred on January 21, 2019, 09:05:47 AM
Guys, this is a 5-1/2 year old post - MY post -LOL.  I don't even own this stuff anymore. Thanks for the comments anyway though!!

Still useful for other, nonetheless.  ( Why is nonetheless one word?)
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Chris Grimshaw on January 21, 2019, 09:24:43 AM
Guys, this is a 5-1/2 year old post - MY post -LOL.  I don't even own this stuff anymore. Thanks for the comments anyway though!!

Woops.
Looks like our friend Fonsy brought it back from the dead.

Chris
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Debbie Dunkley on January 21, 2019, 09:38:28 AM
Still useful for other, nonetheless.  ( Why is nonetheless one word?)

Yes true but I didn't want you to think I was ignoring your advice!
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Debbie Dunkley on January 21, 2019, 09:38:47 AM
Woops.
Looks like our friend Fonsy brought it back from the dead.

Chris
:)
Title: Re: Do I simply need a bigger amp or bridge the one I have?
Post by: Bradford "BJ" James on January 21, 2019, 12:10:07 PM
Woops.
Looks like our friend Fonsy brought it back from the dead.

Chris
Totally jumped the shark.