Amp & Speaker combination and ratings

[coolbaci]

Hi,

This seems like a simple question but it doesn't hurt to ask. We have 4 speakers for foldback that are 300W Program, 600W Max at 8ohms. (Yamaha BR12M)

Just wondering if the Powersoft Q3002 (which I may be able to get a good deal on) would be sufficient.

I read its specs at only 250W @ 8ohms when driving 4 channels.

Considering these are for foldback, is that going to be an issue?

Thanks

[Brad Weber]

The BR12M are rated at 150W 'noise' (continuous), 8 Ohms nominal and a sensitivity of 97dB@1W/1m. The Q3002 is rated at 250W per channel into 8 Ohms but that is an EIA (1kHz and 1% THD) rating, so the rating for full range operation may be a bit lower, probably more like 200-225W.

I can just about guarantee that some will look at these numbers and apply the 'rule of thumb' of having the amp rated 1.5 to 2 times the continuous power rating of the speaker and say you are okay. What many do not realize is that this 'rule of thumb' is not related to what a speaker needs or should have but rather to what may be appropriate for a generic application such as touring or rental where the goal is to balance the maximum output, headroom and reliability of the system in order to support a wide range of potential applications. However, whenever addressing a specific application it can often make sense to look at the needs of that particular application and the specific products involved rather than applying a generic approach.

Since we don't know what levels or headroom may be required for your application, a generic approach is the only option and based on that you should be okay. However that is simply saying the speakers and amps are a reasonable match in general and not that the combination will work or is required for your application. And just for reference, the difference between 200-225W and 300W would be 1.25dB to 1.76dB and thus not likely to be noticeable.

[coolbaci]

Thanks Brad,

Considering we are a small church and this is for foldback with users no more than 2 meters away from the speakers and we don't need levels that high I'd think we would be fine.

[Tim Padrick]

If your monitor levels are not blasting, it should work well. However it seems an exceedingly silly amount of money to spend on an amp when QSC GX series amps would be adequate and appropriate.

[coolbaci]

I've been considering the QSC GX3s new also. I'll see what prices can be done with new GX vs used Powersoft. I am actually shocked at the RRP for the Powersoft.