Question regarding driver replacement.

[needaglock]

Anyone ever try replacing the drivers in an existing cabinet to get better frequency response? The speakers I use for my center and side surrounds have a frequency response going down to 90Hz. They sound fantastic, but the relatively poor low end frequency responce makes bass management problematic with the majority of preamps out there. Additionaly crossing over at 90 or 100Hz creates localization problems and voice carry over into the subwoofer.

The dual 5 1/4" IMG drivers are going to need refoamed soon, so I was debating on just replacing them with aftermarket speakers that had a deeper lower range. I'm waiting on infinity to get me the exact impedance and power handling for the individual drivers so I can find a near exact match, but I'm currently looking at these two as possible replacement units for the cabinet:

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=296-404

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=296-400

I'll be using these with an LCD flat panel, so I shouldn't need to worry about finding magnetically shielding drivers. If I can get away with doing this, I'd like to be able to set the cross over point between 60-80hz. Thoughts?

 

[markw]

You gotta be careful here.

There's more involved than just getting one to fit.

Speaker enclosures are (should be) designed to compliment the exact bass drivers and the crossovers used, and there are many, many different parameters besides size involved here. If you get real lucky, you might find some that sound almost as good, but better? Probably not. Different, yes, but better? I doubt it.

Your best bet is getting the exact replacements. If that fails or is too expensive, go for the re-foam.

 

[Swerd]

There's more involved than just getting one to fit.

Speaker enclosures are (should be) designed to compliment the exact bass drivers and the crossovers used, and there are many, many different parameters besides size involved here. If you get real lucky, you might find some that sound almost as good, but better? Probably not. Different, yes, but better? I doubt it.

Your best bet is getting the exact replacements. If that fails or is too expensive, go for the re-foam.

Everything markw says is exactly on the mark! You'd be better off looking for a new center channel speaker than trying to find "drop-in" replacement drivers that work correctly.

Why do you want to change speakers that you already say "sound fantastic"? Lack of bass performance below 90 Hz in center channel speakers is not really a problem in DD/DTS movies. The center channel is usually almost entirely dialog. If you really hear voices coming out of your subwoofer, lower the crossover point for them if you can. I really doubt whether 5¼" drivers in a small box, vented or sealed, could give you strong bass. Lowering the subwoofer crossover point might not affect the center speaker at all. Try it.

What Left and Right main speakers do you use, and are they used full range? I would rather have main speakers handle the bass and keep it out of the center channel speaker. YMMV.

As far as Aurum Cantus midwoofers, they seem expensive for Chinese made drivers. I looked at their frequency response curves, and as a guess, I think they oversmoothed them to make them look prettier. They look too good to me. Aurum Cantus does have a very good reputation for the ribbon tweeters they make. Their G2 and G2Si tweeters are considered among the very best made. But I have never seen any DIY designs made with Aurum Cantus midwoofers. So, I can't tell you whether they would be any good or worth the money. To my ears, the best 5¼" midwoofer available is the Seas CA15RLY, about $53 at Madisound.

But to repeat what markw said, you have a center channel speaker whose box and crossover was designed for the midwoofers it came with. Unless you get lucky and come up with a replacement driver with exactly the same performance as the originals, you would have worse performance not better.

 

[needaglock]

That's what I thought.

I'll just stick with what I have, and try to find a pre-pro with the right mix of basemanagement options. That 90Hz though is just a difficult frequency to bass manage, it's right at the directional threshold, and most pre-pros will do 80 or 100, but not 90--then there is trying to find a unit which handles each of the channels seperatly. Part of my work around, is for a 7.1 system, I'm putting the sub underneath the flat panel and center channels, so it focuses what voices do come through on the screen, and adds some emphasis (Since, imho, the focus should be on the screen, and with a 7.1 system you end up with more speakers behind you then you do straight ahead.

 

[autoboy]

I was in the Audio Engineering Club in college. We had a competition every year to build your own enclosures. Everybody started with the same drivers. Cabinet and crossovers were your choice. Each team's speaker sounded dramatically different. It was really interesting trying to understand the art and sciene of designing enclosures. When a company designs a speaker, there are many variables that go into the enclosure size and crossover that are dependant on the response of the driver. When you change the driver, all those other parameters also need to change. Simply replacing the driver with another model would most likely make the speaker sound terrible.

Bass below 80-90hz should not be localizable. Sometimes you can route the bass to the front speakers to make up for a small center channel without losing soundstage.