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Alpair 7P & Alpair 12PW combination.

My III LE is in the States. Life Force Design is very highly regarded.
I'm pretty sure LFD in this case stands for Low Fuzzy Distortion. Perhaps there are two companies with the same initials?
This from February 2008 review of the amp in Stereophile:

"In the 1980s, Richard Bews was a research assistant to the legendary Dr. Malcolm Omar Hawksford, manytitled academic and professor at Essex University, a stone’s throw from Clacton-on-Sea. (Hawksford remains a consultant to LFD Audio.) LFD’s first product was a battery-powered phono preamplifier. LFD stands for low fuzzy distortion, a phenomenon first described by Hawksford in an AES paper."

It is difficult to find much about these amps, or this company, outside of the odd forum post or online review. Pretty much all commentary is positive. Many reference Sam Tellig's review quoted above, which went on to say:

"I’ll throw caution to the winds (the Mistral?) and say that the LFD Integrated Zero Mk.III LE is the bestsounding solid-state integrated amplifier I have ever heard. I know of no other integrated, of any type, that sounds quite so right. I base this on listening to four different samples in sessions held nearly 10 years apart. It’s not one of the best, blah blah blah, but the best." Fairly high praise.

We are well off topic now, so I'll stop here. Apologies.
 
Planet 10/Dave

If I may ask your advice, do you think the 12PW would work well as a mid/bass driver in a sealed cabinet and partnered with one of the smaller Mark Audio drivers handling the mid and higher frequencies?

I was thinking of a 7 or 11 MS (or an alternative if you would recommend it) operating down to 200hz or so and then the 12PW working below that.
Assuming this word work, regarding the ’top driver’ what do you think the optimum sealed enclosure size would be and would you operate it full range of with a HPF below 200hz?
Ref the 12PW does it require a large sealed cabinet volume? Would it also be beneficial to run two per side in parallel or would the cabinet for this be huge?

Any thoughts on this or suggestions would be appreciate.

Regards
Alex
 
frugal-phile™
Joined 2001
Paid Member
A12pw-sealed.png


Sealed A12pw does not go as low as Joan/Pencil/other TL, but 30 Hz F10 is not at all bad.

Both Scott & i have done A12pw WAWs, except for the modular A12pw miniOnken, they all use ML-TLs. All use aperiodic midTLs (half [sealed] or quarter wave lines).

I would suggest a 4” driver like A7.3p7hd/A7ms if you want to cross that low. In my wide WAW the MAOP7/A7.3 is crossed at 200 Hz (but to twin SDX7eN. At these frequencies it almost becomes mandatory to biamp. A7ms strengths could really shine in this applucatiion.

dave
 
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Planet 10/Dave

If I may ask your advice, do you think the 12PW would work well as a mid/bass driver in a sealed cabinet and partnered with one of the smaller Mark Audio drivers handling the mid and higher frequencies?

I was thinking of a 7 or 11 MS (or an alternative if you would recommend it) operating down to 200hz or so and then the 12PW working below that.
Assuming this word work, regarding the ’top driver’ what do you think the optimum sealed enclosure size would be and would you operate it full range of with a HPF below 200hz?
Ref the 12PW does it require a large sealed cabinet volume? Would it also be beneficial to run two per side in parallel or would the cabinet for this be huge?

Any thoughts on this or suggestions would be appreciate.

Regards
Alex
I totally get the desire to "roll your own," and if that is your thing then by all means go for it.
If, like me, your desire is to use your woodworking skills to build a speaker that you couldn't otherwise afford I suggest you build the Planet 10/Woden MTM that uses a 7 and a pair of 12pws in TLs. It is astonishingly good.
 
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View attachment 1179098

Sealed A12pw does not go as low as Joan/Pencil/other TL, but 30 Hz F10 is not at all bad.

Both Scott & i have done A12pw WAWs, except for the modular A12pw miniOnken, they all use ML-TLs. All use aperiodic midTLs (half [sealed] or quarter wave lines).

I would suggest a 4” driver like A7.3p7hd/A7ms if you want to cross that low. In my wide WAW the MAOP7/A7.3 is crossed at 200 Hz (but to twin SDX7eN. At these frequencies it almost becomes mandatory to biamp. A7ms strengths could really shine in this applucatiion.

dave
Hi Dave

Many thanks for putting together the information. Very useful indeed and it gives me a very good foundation for me to work out a design. I will also look into your WAW design to see what you have done. AFAIK you are one of the go-to people ref Mark Audio based designs so thanks for the reply!
 
frugal-phile™
Joined 2001
Paid Member
These are our build of the MTM to which Mr 4Fish refers

A12pw-MTM-comp.jpg


Scott’s just uses a single A12pw

Nanotyrranus-tPage.png


Quattrofish also has a thread with his earlier experience with a single A12pw in a big miniOnken.

WAW is a largely unexplored topic with lots or room for innovation. Hopefully fuel to keep the gears turning.

These are the ones i am keeping (fits my living room better — the room pictured is Chris'), one of a kind. A pair of MAOP 7 are awaiting installation

Ellipsa-1st-veneered.jpg


dave
 
Thank's again Dave.

I particularly like your design at the bottom and I think I remember seeing some build details somewhere - I will have a look.

I have attached a 'proof of concept' of what I have in mind. Option 1 is a curved cabinet design visually inspired by some Tannoys and Sonus Faber. Option 2 is a Beonicke W8/W11 inspired design. Both would involve the woofers being driven actively. Clearly I need to do some research on cabinet volume etc. Regarding sealed Vs aperiodic for the full range, am I correct that the latter behaves like a sealed but also gives a slight dipole effect?

Regarding WAW I guess I have just built some, though open baffle. These involve the newish SB Acoustics 8 inch full range and the SB Acoustics and SB Audience bass drivers. The bass drivers are actively low passed at 180 Hz in the baffle and circa 80hz for the 15 inch. The bass side of things is managed by a high quality car amplifier from Genesis using a radio power supply. Probably not for everyone but I like the results!

Regards
Alex
 

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