Driving Acoustat Spectra 1100

dgta

Member
2011-05-30 8:08 pm
Hopefully Acoustat Man will see this, but help from anyone is appreciated.

I just got a pair of Spectra 1100 speakers. Noticed they dip to 2 ohms in the upper frequencies. So I'm trying to figure out what to drive them with.

Will I be OK with a "normal" high power SS amp, or should I only look at amps actually rated for 2 ohm operation? Like maybe a Crown pro amp? I've got a Kenwood Basic M2A on hand, but would like to not fry it.

I don't plan on playing them super loud but they are in a large room (16x30) so will probably require a bit of power.
 
You don't need an amp rated to drive 2-ohms, which is good, since very few amps are so rated. The very low impedance occurs at high frequencies where there is not much musical info, so the actual demands on the amp are not that great.

However, a robust amp is required to wring the best from the speakers, and there are many good choices. Start by trying the ones you have. I would recommend 100-200 watts per channel (8-ohm rating) from an amp that is rated to deliver close to twice that power into 4 ohms. Some amps may still have trouble if they have sensitive protection circuits.

Do remember that ESL's are relatively inefficient, so don't expect concert-hall levels from these speakers. The 1100's are capable of filling a medium sized room with quite acceptable sound levels.

Good luck with your new acquisition!
 

dgta

Member
2011-05-30 8:08 pm
Thanks. I just ran it for a bit with the Kenwood Basic M2A, rated well above 200W @ 8 ohms and something like 350W @ 4 ohms. So far so good, but I've got the HF switch on the speakers set to "low" which is the highest Z position. We'll see how it goes. This amp has very high advertised damping ratio, which tells me it's got very low output Z so hopefully will be OK long term.

Sound levels are more than sufficient with this amp in my large-ish room. No problem there.
 
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I have driven my Spectra 11's with regular home cinema receivers like Denon AVR-1611 (75W @ 8 ohms) and Onkyo TX-NR818 (135W @ 8 ohms) without any issues at all. My living room is quite small, about 200 sq ft, and I don't play super loud so that might help.

I can really recommend the 818, it has lots of power, the suberb Audyssey MultEQ XT32 caibration system and features bi-amping and digital XO of the front speakers.
 
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