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Eminent Technology LFT8B’s reversing woofer polarity

Hi,

I have a pair of the Eminent Technology LFT8B’s and read Dr. Robert E Greene review in the Absolute Sound magazine (2014 I believe) of the speakers where in the review he reversed the polarity of the woofers and said it made a significant improvement. He was going to give the speakers a mediocre review (his words) before doing this and after reversing the woofer polarity he then said they were significantly better and proceeded to give them a rave review. Have any LFT8B owners out there ever tried this? Thank you.

Scot
scothurwitz
douglas_schroeder
3,281 posts
 
I suspect there may have been something wrong with the review pair for that to be effective. 

I reviewed the LFT-8A/B for Dagogo.com  and owned it, even did the "stacked" pairs for a while which was fun.

NO way that speaker gets mediocre rating for its design, build, sound and cost. I think there was something terribly wrong in previous review ( didn't read it, don't care to) to arrive at such a conclusion.   YMMV
bdp24's avatar
bdp24
10,250 posts
 

To turn the LFT-8b in an absolute giant-killer (actually, even in stock form it is), use a pair of GR Research/Rythmik OB/Dipole Subs in place of the LFT’s 8" woofers. Unlike "normal" subs, the OB/Dipole will play up to the 8b’s x/o frequency of 180Hz.

Until you do that, there is a remedy for the resonance in the 8" woofers output (in the 1k-1.5kHz range, way above it's x/o frequency), heard as a low-level "whistle". "Davey" has posted on The Planar Speaker Asylum a simple, cheap low-pass filter that suppresses that resonance to the point of inaudibility. It is just a single cap and resister, placed across the woofer's terminals (on the back of the woofer, not the speaker terminals).

ledoux1238
332 posts
 
I am a newbie to the LFT-8b's having installed them for a little over a month. Robert Greene's review was fresh on my mind when I reversed polarity on the woofers. Expecting some kind of transformation, I heard none! I did it twice, once a week in, and then a few days ago with about 200-250 hrs on the speakers. ( Yes, I've been listening non-stop! )

To be honest, I really wasn't expecting anything major. The speakers wired in their correct polarity was, for me, extremely engaging. I spent most of my time on speaker placement which proved most enlightening. 

BTW @bdp24 turned me onto the ET's. I put the same question to him on another post. And It was Doug's review that moved things forward, having  no dealers nearby. 
scothurwitz OP
113 posts
 
Hi bdp24

I appreciate your input and suggestions. 

I went to GR Research's website and I don't see the Rythmik/OB dipole subs you're recommending. Does GR Research still sell these or have they been discontinued? Do you use one or two and where do you set the crossover point at. 

I don't hear that "low level whistle" from the woofer you mentioned. Just because I don't hear it doesn't mean it's not there and everything won't sound better if eliminated. Do you think it's on every LFT8B ot just on some? 

Thanks for your help.

Best
Scot
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