Quote:
Originally Posted by Alan A
VMPS large is two active woofers - I have one amp bridged to each plus a down firing passive.
The 12” is 4ohm.
The 15” is 8ohm.
I’ve had to turn the bass down 10db (from where the audyssey wants it) to tame the clipping and it’s still not happy.
I could bridge the woofers - so 6 ohms - and biamp into both, but I was hoping for a neater solution. I looked the the crown, but my receiver has RCA preamp outputs for the sub.
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We probably need to clarify a few terms:
-Active speakers generally mean a speaker cab with onboard power amp, often bi-amped with active crossover. Altec, JBL, EV all offered these over the years.
- Passive speaker is one powered by an external amp (most hifi speakers)
- Passive Radiator is an unpowered speaker cone that dampens the speaker enclosure and reinforces LF without a wired audio signal.
If you parallel a 4ohm and an 8 ohm woofer pair, the resulting load is 2.67 Ohm, not 6 Ohm. When paralleled the final load is the sum of the inverse of the combined speakers. This might mean the difference between great LF sound and terrible clipping. Sometimes the details matter.
https://speakerslegend.com/speaker-ohm-calculator
My recommendation- Drive each speaker with an amp that runs comfortably at the given load and output wattage to match the speaker. If the speaker is rated to 400w RMS, run it with 400w RMS. Avoid bridging whenever possible because a bridged amp requires a higher impedance than each separate channel. As I recall the VMPS towers were 100db SPL @ 1W/1m so 400w of clean 4 ohm power would generate 126db @ 1w/1m in your living room. A lotta sound.
An RCA to 1/4" TS adapter cable is a very inexpensive solution to get into a high quality amp to drive the sub.
https://www.amazon.com/s?k=rca+to+1%2F4”+adapter&adgrpid=1337006711754246&hvadid=83563133896220&hvbmt=bp&hvdev=c&hvlocphy=106967&hvnetw=o&hvqmt=p&hvtargid=kwd-83563283314645%3Aloc-190&hydadcr=17955_13444534&mcid=538994a4506b329085f9a9209d528c76&tag=mh0b-20&ref=pd_sl_5rzghrzo17_p