TOPIC:

Hi, I have made the 1st of 2 4 ft3 sealed woofers with 12" SB Acoustics driver. The power spec on the driver is 200w. I don't need any DSP or crossover in the woofer amp; am doing that elsewhere. I'm thinking to use 2 pwr-ice125wd's, each in bridged mode. Is this way too much power for what I need? I know I'm supposed to cut holes in my enclosures and mount the plate amps, but am wondering if it makes much sense to mount them externally so I don't have to cut the holes? Would have to buy/construct a protective enclosure around them to make it safe. Would this be do-able and reasonable, or just dumb?

Are the power output specs for the 125wd the same for 120v or 230v input? For what I'm wanting to do, would I be smarter to just buy a regular 2 channel amp, like the 150w/channel class AB no-name one I've seen on Monoprice? www.monoprice.com/product?p_id=11497. But I like the efficiency of the class D amps for subwoofers, and seems like I'd have plenty of headroom with the 125wd.

Thanks!

Hi, to be honest in the scenario you describe I would get something like a Crown XLS1002. It's less hassle and also less expensive.

The specs for the 125wd are not the same for 120 and 230V, see page 45 of the PWR-ICE manual and if you want the full details google for 125ASX2 PDF.

HTH

PS the driver you are using is the SB34NRX75-6?

Hi, Thanks very much. I like the Crown amp idea. Am thinking maybe to order the 1502 instead of the 1002. Overkill I guess, but it has 6db better S/N spec, and from Amazon is only about $35 more. 300w/chan into 8 ohms. It is sure great to get input from knowledgeable folks.

Yes, my woofers are the RX75-6 you mentioned. I went back and forth with Mr. Linkwitz about woofers and b/c I'm using a piano simulation app, he said a sealed box would be safer b/c the piano app might generate sub-sonic signals that could damage an open baffle speaker. Do you think I've made a good choice for my 20hz to 60hz freq range? I'm using equalization to boost the output of the sealed box down into the 20-30hz range. Do you think it's do-able to properly integrate these woofers with Linkwitz' LXmini or LX521's?

Good point, value wise the 1502 makes sense. I use the XLS1500 (earlier model).

I don't have any personal experience with Linkwitz' speakers, although I have learned a lot from his website. You will be more likely to find this experience at the OPLUG forum. With that said, my own inclination would be to pair those woofers with the LXmini and try a crossover about 120-150 Hz. It also depends on how much output you need.

You will probably find it educational to download Unibox, enter the woofer's parameters and examine the graphs. They will show you the maximum output vs frequency, excursion vs frequency etc at a given power input. I would be a bit careful about pushing those drivers hard at 20 Hz, that is (to my mind) dedicated subwoofer territory. But I'm not sure that's really going to be an issue anyway.

Interesting application BTW. In a former life I was a world famous rock keyboard player. Well perhaps not even slightly famous. And not very talented either LOL. That's why I went back to Engineering school

Edit - link to Unibox: audio.claub.net/software/kougaard/ubmodel.html

I see that some folks don't like the subsonic filter on the XLS amps. Seems inapplicable to my case, since as you say, I should be shooting to extend my response down to ~25hz and that's far enough. (I am not sure which kind of filter to use for that; will do some more reading. So far, I added a shelf filter, but suspect that's not the right way.)

I actually already bought the drivers and parts, and began construction, for 2 LXmini's, but have been worried that they are 2 darn small to make my piano sound like a grand. Linkwitz has them crossed over with larger woofers down around 60hz. I think he is focused on having the sound seem to come from a point source, relative to the size of the room. But your idea about crossing over from the SB 12's at a much higher freq (120-150hz) would give me more SPL, taking load off the LXmini's. I'm intrigued with that idea; I do like several things about the LXmini's and would like to make them work.

Will try Unibox. (And REW too. )

I was also a musician in high school but never tried to make a career out of it... went to engineering school too. I bet you had a lot of fun with that part of your life.

Thanks for all your help!