Very high sensitivity driver and low gain amp

JDUBS · « **on:** 12 Oct 2009, 04:23 am »

Guys

I am finally going to actively triamp my Yorkville Unity speakers. The tweeter, covering 1250hz on up, is a BMS 4550:

http://www.usspeaker.com/bms%204550-1.htm

Those specs say 113db with 1 watt at 1M with a CD horn. I need to "match" this up with a woofer driver that is 94.5db and a trio of paralleled midrange drivers that are somewhere north of 100db (I'm trying to find out exactly). I'm using a DEQX 2.6P directly into the amps which will help to equalize gain but I'm thinking that maybe using a low gain amp (like a First Watt F3 at 13db) would also help the situation. The gains of the amps for the midrange drivers and woofers will likely be the more traditional 24-25db.

Does this make sense?

Thanks,
Jim

doug s. · « **Reply #1 on:** 12 Oct 2009, 04:46 am »

i use a deqx, triamping; the speakers have similar sensitivity, but the amp on top is much more sensitive; i use rothwell 10db attenuators plugged into the amp, between the deqx & the interconnects. you could also try goldenjacks; i have never tried them, but a couple folks have said they are even more transparent than the rothwell's. hard to imagine; i have never heard the rothwells veil anything... anyway, you could try using them in front of the amps driving your more sensitive drivers, instead of looking for an amp of lower sensitivity...

http://www.rothwellaudioproducts.co.uk/html/attenuators.html

http://www.goldenjacks.com/

doug s.

richidoo · « **Reply #2 on:** 12 Oct 2009, 07:35 pm »

DEQX being 32 bit DSP has a lot of headroom to attenuate digitally without any harm to your source resolution. Digital attenuation adds no noise when there is sufficient headroom. Pick an amp for the sound, not for the gain because that tweeter will reveal any kind of harshness without a passive crossover there to dull it. F3 is probably an excellent choice for its tone, and lowish gain is a bonus. I have heard F5, it is gorgeous.

JoshK · « **Reply #3 on:** 12 Oct 2009, 08:11 pm »

Don't forget you need to add CD eq to the tweeter so you loose about 6db/octave. I think that'll work out to about 10-12dbs shaved off the tweeter's sensitivity.

JDUBS · « **Reply #4 on:** 13 Oct 2009, 12:29 am »

This is helpful, thanks fellas. My line of thinking was that I could use the lower sensitivity amp in lieu of in line attenuators if possible.

Josh, thanks for the note on cd eq. I pulled the sensitivity spec for the BMS driver with a cd horn, so I think that the sensitivity loss is already taken into account. Emphasis on "think". That site also lists 118db with a "plane wave tube".

richidoo, I totally agree. I had always wanted to try an F3 and this application gives me a good excuse!!

-Jim