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18" Coaxial driver pair for sale

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For sale: A pair (two) P.Audio BM Series 18” coaxial drivers. Price for quick sale at $750 (USD) for the pair. These legendary drivers are no longer made and now a rare find. P.Audio no longer offers BM Series 12”, 15” or 18” coaxials. The 18” is model number BM-18CX38. Manufactured in June, 2007. Originally purchased in late 2008. All original.

This is a coax driver with 18” woofer and 1.4” exit compression driver attached. Condition is used. Mechanically excellent, but as these were used for audiophile demonstration purposes, they do show some cosmetic wear. Please refer to photos. They have a very low play time with low powered amplifiers and have never been used in a professional application. One owner.

T/S parameters for the woofer section are measured as:
Woofer “A” Woofer “B”

Re (ohms) 7.63 7.59
Fs 37.9 38.7
Vas (liters) 457 469
Qts .44 .46
Power (RMS) 350 350
X-max 4.5 4.5
SD (sq. cm) 1244 1244
Voice coil 4” 4”
Ref efficiency 99.2 db/watt/meter

H.F. driver is P.Audio BMD740

H.F. DCR 6.63 6.56
H.F. F/S 498 528
Voice coil 3” 3”
Factory rated @ 75 watts RMS @ 500 Hz

H.F. is loaded by a 3.25” exit tapered coax short horn and 16” woofer cone. Loads down to 800 Hz.

I have used these on open baffles of 22” W X 50” H with 8” wings where they work surprisingly well down to about 45 Hz with proper crossover. They will also work well in a large 140 liter stuffed and sealed box down to about 49 Hz -6dB. Add a sub- woofer if you feel the need. However, most music does not require a sub.

Also good in a 300 liter ported enclosure (Thiele QT alignment) with a 12” dia. port 11” long tuned to 37 Hz. (-3db)

The best description of these is that are a “real man’s speaker - nothing wimpy here”. Real life dynamics, scale, force.

I have owned, at one time or another, several 15” Altec duplex coaxials, i.e., 604 D, E & K and 605 A&B. Set up properly, the BM18 is easily superior overall and vastly superior in bass extension, midrange dynamics and smoothness.

I’m selling these simply because I have way too many speakers and need to clean house. It’s time to let these go to a good home where they will make someone very happy.

They will be shipped in 2 boxes by your choice of carrier. Each box is 20” x 20” x 11”. Shipping weight of each box is approximately 50 pounds. Buyer pays actual shipping costs and insurance from Texas zip code 78028.


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Last edited:
Joined 2004
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I have heard and worked with these drivers (John B's set) and can attest to them being amazing. They are maybe the most dynamic drivers I've ever heard, besting other coax or single driver I know. They also do all the fun thing that coax do so well, like image, space, pinpoint location, depth. They just do it bigger and better than any other's I've heard. They are energetic, life-size speakers that take you into the recording.

I helped work on an early version of the PB crossover with John, which made for a learning experience with tonal balance and space. Ask me or John about them, they are extraordinary. If I still had a dedicated listening room, I'd own them.
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