danny_66 - thanks for the info! Never heard of it till now.
Ebay has some sylomer vibration isolation brackets at a quite reasonable price.
VibroNet PP-35 Vibration Isolation Ceiling Hanger | eBay
Looks like the device would substitute for my "post" quite nicely. Sure wish I could have one in hand to see, before purchase -
Ebay has some sylomer vibration isolation brackets at a quite reasonable price.
VibroNet PP-35 Vibration Isolation Ceiling Hanger | eBay
Looks like the device would substitute for my "post" quite nicely. Sure wish I could have one in hand to see, before purchase -
Make sure you buy the Solymer in the correct stiffness for your application.
I used the brown SR110, that has an optimal damping at 0.7kg/cm²
You can find Sylomer more in the industrial/construction shops:
wywlngh.com
akustik.com
atis.com
I used the brown SR110, that has an optimal damping at 0.7kg/cm²
You can find Sylomer more in the industrial/construction shops:
wywlngh.com
akustik.com
atis.com
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I've only read that it's the case and theory appears to support it, can you flesh out your post at all? What's too close and what is it that's heard and why?
Too close is FR125 or FE127 in PAWO, going from 4 to 4.75” helped clean things up a lot.
And Chris is convinced that much of the poorish performance of out Eikona can be attributed to the shaloowness of the box. I will be looking at that eventually.
dave
And Chris is convinced that much of the poorish performance of out Eikona can be attributed to the shaloowness of the box. I will be looking at that eventually.
dave
Not so much “trained” in a classical sense, but they have certainly been rode hard and put up wet more than a few times since starting out in this addiction in the mid ‘60s.
As to the specific postulation re the implementation with Eikona, as Dave implied it was not the first of his wide baffle/shallow designs using FR drivers with lightweight cones in which we found some coloration. The PAWO was bamboo plywood, into which it was easy enough to machine a “supra-baffle” to both accommodate a different driver than originally used (i.e. Fostex FE127 replaced CSS FR125, IIRC), and increasing the spacing to rear wall by approx 1”/25mm.
The “Hawking Memorial” monolith had a very specific aesthetic intent and dimensions, and the material chosen for finish (matte finish HP plastic laminate) doesn’t easily lend itself to reworking. I’d loved to have been able to try these drivers in another competently designed enclosure, but life and retirement intervened.
As to the specific postulation re the implementation with Eikona, as Dave implied it was not the first of his wide baffle/shallow designs using FR drivers with lightweight cones in which we found some coloration. The PAWO was bamboo plywood, into which it was easy enough to machine a “supra-baffle” to both accommodate a different driver than originally used (i.e. Fostex FE127 replaced CSS FR125, IIRC), and increasing the spacing to rear wall by approx 1”/25mm.
The “Hawking Memorial” monolith had a very specific aesthetic intent and dimensions, and the material chosen for finish (matte finish HP plastic laminate) doesn’t easily lend itself to reworking. I’d loved to have been able to try these drivers in another competently designed enclosure, but life and retirement intervened.
Thanks Chris, when you say colouration what do you mean, some frequency range leaking through the cone?
Asymmetrical non parallel walls spread the frequencies.
Held firmly. It's movement, opposite and equal and all that, is not linear as the driver has mass so it introduces a linear distortion. Possibly masking the more subtle sounds. I woudl have to think about that.
Like anything, you can reach diminishing returns pretty quickly. For high power subs, I think I would oppose them. Actually, if I had the physical space I would have on my current build, but the sub has to sit in a cubby hole, so both fire forwards.
Held firmly. It's movement, opposite and equal and all that, is not linear as the driver has mass so it introduces a linear distortion. Possibly masking the more subtle sounds. I woudl have to think about that.
Like anything, you can reach diminishing returns pretty quickly. For high power subs, I think I would oppose them. Actually, if I had the physical space I would have on my current build, but the sub has to sit in a cubby hole, so both fire forwards.
It's more probable that it's to do with the other dimensions and/or the alignment of the enclosure than the depth per se. It could also be the change in frequency of the reflection was beneficial to the overall frequency response.
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Re standing waves, why does SL mention 1/16 of a wavelength here?
Frontiers
"I am of the opinion that the effect is most notable in the low hundreds of Hz region, where stuffing materials are ineffective and the internal dimensions not small enough for the internal air volume to act as a pure compliance. Consequently, enclosures should be either very small (less than 1/16th of a wavelength) or extremely large, both of which are not very practical for different reasons."
Frontiers
"I am of the opinion that the effect is most notable in the low hundreds of Hz region, where stuffing materials are ineffective and the internal dimensions not small enough for the internal air volume to act as a pure compliance. Consequently, enclosures should be either very small (less than 1/16th of a wavelength) or extremely large, both of which are not very practical for different reasons."
Most notable on vocals, I’d best describe it as inordinate reverberation and slurring of percussives and sibilants. I discerned similar type of coloration on some early BLH builds with too shallow or badly damped driver coupling chambers - particularly e.g. the original iteration of Ron Clarke’s A126, or the Buschhorn I. My intuition at the time was that reflections off the close back wall - even when “lagged” with felt, etc - was causing intermodulation of paper cones (weren’t using Mark Audio metals at the time), rather than being absorbed/dissipated by damping material or diffusion schemes.
Acknowledging that it’s as likely to be confirmation bias as anything else, this is likely one of the reasons my favorite enclosures to this day are generally deeper than wide - such as Scott Lindgren’s Pensils. Spoiler / redundancy alert; I’ve built / modified a few different types of enclosures, including at least one of each of Scott’s more common families - and a few of Planet10’s more elaborate designs - and find the Pensils to be a great compromise/balance of performance and ease of build.
Armchair keyboard warrior second-guessing aside, there’s still much to be gleaned from Siegfried’s lifetime body of work - but why exactly the 1/16th wavelength is a good question.
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Thanks for your thoughts. I think the sound was more likely travelling through the cone than modulating it, I might be wrong. Measurements could help, did you make any?
Yes, half wavelength, I believe, is what matters re standing waves, never read anything like 1/16 before.
Yes, half wavelength, I believe, is what matters re standing waves, never read anything like 1/16 before.
That corresponds to the experience I had with a mid in a small box.
I recently finished version 2 of my speakers to solve this problem.
The mid cabinets went from a 3.5 liter closed box in v1 to a 10 liter aperiodic vented cone shaped box in version 2,
this made a huge update to the sound:
with the small closed box in v1 I didn't get the Accutons C173-6-090 to sound completely good, sometimes it sounded nasal, congested,
I suspect it was due to the backwaves of the cone bouncing around in the small closed box.
With the new 10 liter cone shape tapered box (45cm long), the backwave is completely absorbed, also thanks to the very good Twaron Angelhair (stuffed 3gr/l)
Now it sounds much more natural, open and dynamic.
Inspiration for the larger cone shaped mid comes from Troels,
the venturi vent in the Avalon clone and the XTZ divine.
My findings correspond to Troels ones, see halfway "Mid cab vent"
I recently finished version 2 of my speakers to solve this problem.
The mid cabinets went from a 3.5 liter closed box in v1 to a 10 liter aperiodic vented cone shaped box in version 2,
this made a huge update to the sound:
with the small closed box in v1 I didn't get the Accutons C173-6-090 to sound completely good, sometimes it sounded nasal, congested,
I suspect it was due to the backwaves of the cone bouncing around in the small closed box.
With the new 10 liter cone shape tapered box (45cm long), the backwave is completely absorbed, also thanks to the very good Twaron Angelhair (stuffed 3gr/l)
Now it sounds much more natural, open and dynamic.
Inspiration for the larger cone shaped mid comes from Troels,
the venturi vent in the Avalon clone and the XTZ divine.
My findings correspond to Troels ones, see halfway "Mid cab vent"
Not less, earlier, and stronger (given the 6dB/doubling rolloff with distance)
dave