what to do with Neo8s + 12" midbass + 18" subwoofer: large box or OB? - Page 3 - diyAudio
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Old 17th August 2013, 01:57 AM   #21
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Quote:
Originally Posted by zmyrna View Post
LineSource,
I have seen your older posts; you seem to have had some OB experience.
What are you listening now? EconoWave?
What did you think about OB? Why did you switch?


For "well recorded" music in our (650 sq ft) living room we favor the Apogee Full Range ribbon linesource speakers and thousands of Krell amp watts. Stig's B&G750 planar linesource with multiple 21" woofer H-frames could produce a similar audio illusion. We put diffusers behind our Apogee speakers to help create a natural in-room audio illusion from the dipole effect. Stig puts absorption behind his speakers to remove the upper freq dipole effect, plus diffusors behind the listener... different audio illusion. I have built dipoles using standard speakers(daughter took them) but favor linesource dipoles.

For BluRay movie audio while the family sits on one or two couches in the media room we favor a sealed box 3-way(Lambda TD15S + TD10M + SEOS12 with B&C 250 CD) because of the dynamics and controlled directivity. Compression drivers with plastic domes sound "OK".


From what I have read on tinnitus, the most common condition is a continuous high pitch "sine wave" in one ear. The common audio test is to listen for hours to headphones with a Hi-Q notch filter of say +/- 200Hz around the "sine wave" frequency in the bad ear. If this experiment provides some comfort and short term reduction in tinnitus tone amplitude, a similar filter can be applied to both speakers, which also have a narrow polar pattern around the tinnitus frequency to minimize room reflection generated harmonics. Dipoles with absorption behind the speaker(like Stig) could remove tinnitus frequency harmonic reflections from reaching the bad ear. Still need a notch filter. Still need hundreds of watts of dipole equalization.

IF, IF, IF your tinnitus matches my simple guess, then you might look at a 40x40 polar Synergy Horn, or a speaker similar to the Daniel Hertz M1 which has a 40horizontal x 60vertical short horn. Test a compression driver with a plastic dome and at least LR4 Xover slopes to beat down the dome and 12" midbass cone breakup energy. Speaker cone or compression driver dome breakup might generate tinnius frequency energy.


MDF panels + MDF quarter rounds + basic black paint might hide nicks from frequent moves.
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Old 18th August 2013, 08:33 PM   #22
zmyrna is offline zmyrna  United Kingdom
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Nate, I just realized that you are the creator of the dipole disorder.
Yes, the power DACs are Panasonic receivers.
And it is true that with the nanodigi and high EQ, they are not very happy.
I was raising the volume of the larger driver to match the midbass.

Anyway.

OBs are going to be a nightmare to place optimally in London style accommodation. My large boxes will be standing by the wall, which is far more convenient.

Line, I will build the large boxes with the drivers I have. If it does not work very well, I might throw in a 1" CD later on.

Thanks for the advices and please keep them coming.

Here are some pics of the drivers and my baffles.
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File Type: jpg P1020535.jpg (431.8 KB, 272 views)
File Type: jpg P1020536.jpg (411.2 KB, 261 views)
File Type: jpg P1020537.jpg (338.9 KB, 258 views)
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Old 18th August 2013, 08:58 PM   #23
zmyrna is offline zmyrna  United Kingdom
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I don't have the capacity to do the rounded cabinet edges.
Asymmetric placement and some foam treatment on baffle will have to do.
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Old 18th August 2013, 09:04 PM   #24
ScottG is offline ScottG  United States
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Quote:
Originally Posted by zmyrna View Post
I don't have the capacity to do the rounded cabinet edges.
Asymmetric placement and some foam treatment on baffle will have to do.
Bendy MDF

http://www.tapeease.com/2rounds.htm
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Old 19th August 2013, 06:07 AM   #25
NEO Dan is offline NEO Dan  United States
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12PR300 √
Plastic CD = 2408H√
Small √
Big sound √
No corner rounds √
Efficient √


Click the image to open in full size.

Click the image to open in full size.
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Old 19th August 2013, 04:02 PM   #26
zmyrna is offline zmyrna  United Kingdom
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Scott,
Thanks for the links.
I could give it a go for round edges on a smaller built.
My box is 107x79x44cm.
And I don't have a workshop or a garden shed.
It is already proving very difficult to build the boxes.
On top of that, I really want to have sth similar in style to vintage JBL monitors.
As you can see, my drivers will be placed asymmetrically on the baffle.
I also plan to cover the baffle with 5cm thick acoustic foam. That will help with the retro look too
My tweeters are horn loaded, so diffraction won't be an issue at HF (>4-5000Hz).
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Old 19th August 2013, 04:09 PM   #27
zmyrna is offline zmyrna  United Kingdom
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Dan,
Nice speakers.
Sealed box?
Can you please give more info?
Dimensions? Volume?
Model of CD? Crossover point? Active/passive?
How do you like the Faital 12"? (compared to similar drivers)
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Old 30th August 2013, 11:32 AM   #28
zmyrna is offline zmyrna  United Kingdom
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I am going to start gluing my enclosures soon.
In my current baffle set-up, Fountek CD3.5H is placed on top of B&G Neo8S.
I can cross the CD3.5H as low as 2500Hz.
But I would much prefer to have the CO point around 5000Hz.
However, if I CO around 5000Hz, the CTC distance will be over 1 wavelength at the current driver placement.
At 5000Hz CO, I can stay within 1WL if I place the CD3.5H on the side of Neo8s.
Many say this would create very bad horizontal lobing.
So which driver placement and configuration is the best compromise you think?
(while I can still change the baffle design)

Last edited by zmyrna; 30th August 2013 at 12:00 PM. Reason: bad english
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Old 2nd October 2013, 11:13 AM   #29
zmyrna is offline zmyrna  United Kingdom
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Large vintage JBL type enclosure had three drawbacks:
1. sharp edges = diffraction
2. vibration from 18" bass driver affecting other drivers
3. Neo8S had to be in a sealed enclosure (people like it open back)

So a change in plans over here.
18" Faitals will be in two separate BR enclosures (stereo subs).

Main speakers will be 3 way, in a wide and shallow enclosure with round side panels - similar to SF Stradivari/Elipsa.

h95cm x w64cm x d20cm

12" Faital 12PR300, will be sealed in about 30l.

Neo8S will be horizontally placed and open back, and Fountek CD3.5H on top of it vertical: top part of the speaker will be very similar to Martin Logan Mosaic (pic) but on a slightly wider baffle.

Wood and MDF cut and ready. Already started gluing. Photos coming in the weekend.
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Old 2nd October 2013, 05:34 PM   #30
Eldam is offline Eldam  France
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Hi,

A 18" is difficult to stop and don't come back rapidly in initial position...difficult match with a planar, No ?

Studiotech, I look at your design from sevral weeks now and have a question which think is not OT : with an alone NEO 10 in a normal living room , which should you use for xover in the low ? 500 ? more ? thinking maybe like you with a cover felt la Dalquyst to have a load behind. Does it need more bafle step to have lower crossover and did you test it ?
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