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[Silas Pradetto]

I just picked up some RS880s for fun and want to switch the woofers to neo to save some weight. (Yeah, I know the implications for the crossover and matching impedance, etc). Now I'm not an expert at T/S parameters, so I don't really know how close the parameters of the new woofer need to be to match and be compatible. Anyone care to assist? I checked the Eminence neo woofers and none of them seem that close.

[Elliot Thompson]

Save some weight?

Those speakers are light already based on the parameters.  

I would suggest you leave the loudspeakers (they are not woofers) as is. There are no off the shelf drivers that matches those TS Parameters.

It is really efficient in addition to offering a very low resistance. I take it they were in a horn-loaded cabinet or possibly column speakers and wired series-parallel?

These drivers must be very old.


Best Regards,

[Silas Pradetto]

Elliot Thompson wrote on Mon, 03 August 2009 13:57

Save some weight? Those speakers are light already based on the parameters.   I would suggest you leave the loudspeakers (they are not woofers) as is. There are no off the shelf drivers that matches those TS Parameters. It is really efficient in addition to offering a very low resistance. I take it they were in a horn-loaded cabinet or possibly column speakers and wired series-parallel? These drivers must be very old. Best Regards,

Yes, they are old. They're from RS880s which are mid-80s I believe, and yes they are horn loaded. I guess the 250 pound box isn't going to notice a 20 pound weight reduction anyway.

Thanks Elliot!

[The Guy]

Silas Pradetto wrote on Mon, 03 August 2009 10:47

I just picked up some RS880s for fun

What on earth were you thinking....

[Silas Pradetto]

Jim Bowersox wrote on Mon, 03 August 2009 17:05

Silas Pradetto wrote on Mon, 03 August 2009 10:47 I just picked up some RS880s for fun What on earth were you thinking....

I was thinking "DJ fills and sidefills for rappers"

[Elliot Thompson]

Silas Pradetto wrote on Mon, 03 August 2009 19:35

Yes, they are old. They're from RS880s which are mid-80s I believe, and yes they are horn loaded. I guess the 250 pound box isn't going to notice a 20 pound weight reduction anyway. Thanks Elliot!

The good thing about cabinets from the 1980's downward is their versatility. You can upgrade the drivers if you need something that can handle more power. The bad thing is if the box was designed around the driver the response won’t be the same as the original.

If you choose to go that route, you'll need to reinforce the flares for it was standard to have 5/16" thick wood if it is housed in a straight horn.

With a 1.8 mm Xmax you, are lucky if the loudspeaker will survive over 200 watts getting a 60-Hertz signal. It offers a very high no.% and, is louder than EVM 15L. However, it offers a smaller xmax (nearly half) than the whole EVM line. This is why, I called it a loudspeaker and, not a woofer for it falls within that “lead loudspeaker” category.

It may perform excellent from 750 – 1.5 kHz and can probably make it up to 6 kilohertz if the voice coil is 2.5 inches or smaller.

Please keep in mind I have no idea what an RS880 looks like so, I basing everything from the TS Parameters you posted.

Best Regards,

[Chris Van Duker]

I guess I should wade in here since I've actually done what you're asking about. I bought 8 RS-880 cabinets a few years ago. Half of them had the woofers replaced by B&C 15HPL76, and the other half had the original Community woofers -- though they were so brittle that they cracked when touched.

The B&C drivers worked well, but I was reluctant to load the same drivers into the other 4 cabinets because the driver frame is just slightly too large for the fiberglass lip that it mounts to in the cabinet. The four which had been switched over, had that lip removed, and I really wasn't satisfied with the resulting fit of the drivers, or in the way they were mounted.

I ended up loading the other cabinets with Eminence Kappalite 3015s, and have been satisfied with the results -- and they fit in the cabinets without modification. The most divergent specs are the Qe and Vas, while others are closer.

Subsequently I replaced the B&C drivers with more of the 3015s, as the B&C woofers were also getting a bit long in the tooth, so now all 8 are loaded identically.

The crossovers were in various states of disrepair, so I run the boxes biamped, with my own crossover between the mid and high horns. All the highs have been switched over to B&C DE250, which is a driver I really like. So at the moment, the only stock driver is the M200 midrange.

[Chris Van Duker]

These look a lot closer, spec-wise, than anything else I've found so far:

http://www.rcf.it/en_US/web/rcf/products/precision-transduce rs/neodymium-low-frequency-transducers/mb15n351

[Silas Pradetto]

Chris Van Duker wrote on Tue, 04 August 2009 16:05

These look a lot closer, spec-wise, than anything else I've found so far:  http://www.rcf.it/en_US/web/rcf/products/precision-transduce rs/neodymium-low-frequency-transducers/mb15n351

Those look pretty awesome, can anyone (Elliot) confirm that these would work? They'd be especially suited if they were available in 4 ohms.

[Elliot Thompson]

The RCF Chris suggested would be as efficient as the Electrovoice EVM 15B Series II with a similar frequency response. It is a good replacement for the driver you are currently using.

What you lose in efficiency (1 - 2 dB less) you will gain with more power handling.

A 4-ohm version will not be louder than an 8-ohm version.

The only difference is where you stand on amplification. If your amplifiers deliver 1000-1300 watts @ 8 ohms, it would be safer to use the 8-ohm version  @ 1000-1300 watts than, a 4-ohm version that will see 2000-2500 watts.

Using 4-ohm drivers only benefit those who don't have enough amplification to drive the loudspeaker at the recommended wattage by the manufacture at 8 ohms.

Bear in mind, these drivers are Mid-Bass loudspeakers not woofers. There will still be a large reduction below 75 Hertz in terms of output. However excursion headroom will be more than the stock driver sitting in the horn at the moment.

You should not have any problems attaining frequencies ranging from baritone male vocals to tenor female vocals with this driver. Add the horn in the equation and, you will have a very High SPL horn-loaded cabinet under today’s standard.  

The difference in tone amongst the old driver & RCF is merely adjusting your parametric. If the box begins to ring when feeding it 600+ watts at certain frequencies, just dampen the flares with any type of dense fabric material inside the box.

Best Regards,