High sensitivity OB bookshelf speakers with Audio Nirvana FRs

Fiftyfifty

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They are finally live!
Those who have seen my other threads would know that I was looking for bookshelves that could be driven by my 1wpc Linear Tube Audio mz2. Sensitivity needed to be > 97db. The guys at LTA recommended either Zu Audio or Omega. Prices were high and reviews were mixed. Encouraged mainly by fm @yogibear I decided to give high sensitivity single driver full rangers a shot.
I used 12" AN Ferro Super drivers and 1½" steam beech panels. The design was largely based on AN recommendations + trusted sources.
Dimensions are 39"H x 25"W. The two side panels are 15" at the bottom tapering to 9" at the top. The front panels are single cuts of wood with no joints. All panels are 1½" beech.
The drivers were first mounted on 15 x 15" ply using SS bolts and Nyloc nuts. The rim of the driver was covered with double sided adhesive tape to provide some isolation from the ply on which it was mounted. The ply with the driver was then bolted to the inside of the front panel with SS bolts and insertable L-nuts. There's an 8mm rubber sheet isolating the ply from the panel - the bolts go through the ply and the isolating rubber sheet into the panel.
I did not personally do the carpentry - just guided my very cooperative and willing carpenter, who shared my thrill of doing something new. Finally polished by a very experienced polishwalla to give it a dull but silky finish. The suckers are huge, each weighing around 40kgs.
The attached pictures tell the story.
I'm not a DIY person and didn't want to experiment with different designs or repeated voicing. I wanted to get it done in a single attempt. I had followed what appeared to me as sound logic, but was prepared to be disappointed. I wasn't! Initially the treble was harsh and the bass non existent. Just about 10 hours of burn in and they started to sound sweet. The midrange beats anything I've heard on electrostats. Very resolving and amazing imaging. A good full ranger has to be heard to be believed! The bass, in my guess, goes down to around 60-70 hz, the rest is taken care of by my REL t9i.
I'll post what happens after full burn in.
Special thanks to FM's @yogibear , @Kannan and @Beginner_N for all their encouragement, suggestions and supported. Also want to thank all those who responded to my other threads.
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Congratulations Kishore. they look as great as they must sound, I am sure. must be even more satisfying to go with your gut and have the results. I shall follow this thread closely.
 
Waiting patiently for listening impressions...
Is a sub connected or the bass from the drivers enough?
Hi,
Like I said in my first post, the speakers are very very resolving and great horizontal imaging. Stage depth is not too great but that is likely to be impacted by speaker placement, which I'm yet to experiment with. Midrange appears to lift itself and appears in very sharp focus, without any loss in other frequencies. Therefore vocals and jazz are particularly enjoyable. Bass is clearly insufficient at the moment and I use a sub. Let's see what changes after about 100 hours of burn in!
 
Hi,
Like I said in my first post, the speakers are very very resolving and great horizontal imaging. Stage depth is not too great but that is likely to be impacted by speaker placement, which I'm yet to experiment with. Midrange appears to lift itself and appears in very sharp focus, without any loss in other frequencies. Therefore vocals and jazz are particularly enjoyable. Bass is clearly insufficient at the moment and I use a sub. Let's see what changes after about 100 hours of burn in!
Yes, true! A meters space behind them would do a world of good! Real estate hits hard on our passion!!!! you must post a youtube video of it singing!!
 
Kishore, since you doubled on the baffle with a rubber pad in between, the driver could be well recessed from the front baffle. This may cause diffraction issues. You may want to chamfer / slope the front baffle opening edges.

Second suggestion is, if you can get hold of some felt, try putting it all around the rear of baffles. It makes significant difference.

Sound stage is suffering mainly because of less clearance from sides and rear else OB shine both in imaging and soundstage.
May not be visible in the pictures, but the front baffle is nicely chamferred.

I have sourced some nice felt. Will try that and also positioning the speakers after burn in.

Thanks
 
Hi,
Like I said in my first post, the speakers are very very resolving and great horizontal imaging. Stage depth is not too great but that is likely to be impacted by speaker placement, which I'm yet to experiment with. Midrange appears to lift itself and appears in very sharp focus, without any loss in other frequencies. Therefore vocals and jazz are particularly enjoyable. Bass is clearly insufficient at the moment and I use a sub. Let's see what changes after about 100 hours of burn in!
Hi Kishore. Though you have already shared your initial impressions of the beauties. May I ask, how are the speakers doing post burn in and all and after you having listened to them more extensively now.

Any comparisons/differences with ported/other speakers you have used?
 
Hi Kishore. Though you have already shared your initial impressions of the beauties. May I ask, how are the speakers doing post burn in and all and after you having listened to them more extensively now.

Any comparisons/differences with ported/other speakers you have used?
Sushant, I'm very happy with these speakers. With expended use, the bass has improved considerably, so that it now crosses over smoothly into the frequencies handled by my subwoofer.
How do I describe the sound? It's very unique. The mid-range is exquisite. Highs as in cymbals and hi-hats are reproduced very well. Long listening sessions are comfortable. I would say that the bass is weak in the 70 - 110 hz region. Another negative is that they are pretty unforgiving - poor recordings can sound harsh. These are definitely not all -purpose speakers, but for small group jazz music, vocals, acoustic recordings/unplugged, Indian classical, etc. I just love them. I need to also add that this is my second setup and, therefore, I have the option of listening only to music that these speakers like.
More over a glass of Feni in Goa ;)
 
Sushant, I'm very happy with these speakers. With expended use, the bass has improved considerably, so that it now crosses over smoothly into the frequencies handled by my subwoofer.
How do I describe the sound? It's very unique. The mid-range is exquisite. Highs as in cymbals and hi-hats are reproduced very well. Long listening sessions are comfortable. I would say that the bass is weak in the 70 - 110 hz region. Another negative is that they are pretty unforgiving - poor recordings can sound harsh. These are definitely not all -purpose speakers, but for small group jazz music, vocals, acoustic recordings/unplugged, Indian classical, etc. I just love them. I need to also add that this is my second setup and, therefore, I have the option of listening only to music that these speakers like.
More over a glass of Feni in Goa ;)
That's great. They seem to be ticking quite a few boxes. Plus the joy of building/having them built, yourself. Thanks for the feedback. Will take you up on the offer soon :)
 
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