resonance
Re: stored energy?? Post #718
Not to be argumentative, but the magnitude of said resonance and its effect on the sound is what is an issue. If the level of supposed microphonics is way way below the noise threshold, there is no physical means of distinguishing it, human or otherwise. As I've been involved in building detectors for radio astronomy and microwave communications, where amplifiers, discriminators, mixers bolometers, and the like are run near absolute zero and signals on the order of a few tens of degrees are being measured from light years away, I feel confident that the microphonics induced in this marble, wires, transistors, etc from audio pursuits are absolutely
swamped by many other far greater effects (mostly as thermal noise). So the theory I guess is that the resonant frequency of the marble amplifies the harmonics (be they of femtoscopic amplitude) until they are audible? Not likely.
I'll continue to pursue improvements in the weakest link by far of the audio chain.. the speaker and speaker/room interface.
(sorry to run off topic...)
John
Re: stored energy?? Post #718
Not to be argumentative, but the magnitude of said resonance and its effect on the sound is what is an issue. If the level of supposed microphonics is way way below the noise threshold, there is no physical means of distinguishing it, human or otherwise. As I've been involved in building detectors for radio astronomy and microwave communications, where amplifiers, discriminators, mixers bolometers, and the like are run near absolute zero and signals on the order of a few tens of degrees are being measured from light years away, I feel confident that the microphonics induced in this marble, wires, transistors, etc from audio pursuits are absolutely
swamped by many other far greater effects (mostly as thermal noise). So the theory I guess is that the resonant frequency of the marble amplifies the harmonics (be they of femtoscopic amplitude) until they are audible? Not likely.
I'll continue to pursue improvements in the weakest link by far of the audio chain.. the speaker and speaker/room interface.
(sorry to run off topic...)
John
Re: Re: amp design
I'm not a marlble man realy, but I like to to produce good-looking goods
I know several boys, hows prefer heavy chasses against slight ones, but first thing now - view, generous, high-minded, appropriated interior, for sweet home, not for basement.
that's why I being made all of acoustic, using precious materials.
apropos, you'll spend almost the same money for make it by wood.
anyway - thank you.
planet10 said:
Cool... should we just start calling you the "marble man"?
I'm not a marlble man realy, but I like to to produce good-looking goods
Stocker said:
I know several boys, hows prefer heavy chasses against slight ones, but first thing now - view, generous, high-minded, appropriated interior, for sweet home, not for basement.
that's why I being made all of acoustic, using precious materials.
apropos, you'll spend almost the same money for make it by wood.
anyway - thank you.
Re: resonance
You use a lot of big words, so I'm sure you know more about the scientific mechanisms than I do, but I must say for other people's sake that I do hear differences in equipment feet, racks, and chassis damping. People must try it, if they are to escape the potential quadmire of sluggish sound. (I once had paving slabs on my equipment rack to 'damp vibrations' - once they'd gone what a relief! The sound was freed!)
edit: realise I might have sounded sarcastic. I respect others' opinions and right to disprove my ideas and debunk my myths.
auplater said:
You use a lot of big words, so I'm sure you know more about the scientific mechanisms than I do, but I must say for other people's sake that I do hear differences in equipment feet, racks, and chassis damping. People must try it, if they are to escape the potential quadmire of sluggish sound. (I once had paving slabs on my equipment rack to 'damp vibrations' - once they'd gone what a relief! The sound was freed!)
edit: realise I might have sounded sarcastic. I respect others' opinions and right to disprove my ideas and debunk my myths.
Well if this works you'll see my first DIY attempt taken from a kit design that I modified slightly (blindly). The sides are at 95 degree angles to the front. The crossover was modified from the original to use all mundorf components. The finish is well I'll answer that if someone asks to avoid unnecessary ridicule.
Attachments
Well the story goes like this. I went to the local shop and found nothing acceptable under €600 ea. (US $780). So I decided the time has come to build some. After considering different designs, and talking with a couple of gurus I decided on the Sidewalk kit from Intertechnik.
They only had one slanted side and my wife correctly stated that in all likelihood people would think I screwed up if only one side was slanted so I slanted them both. The added volume had a positive effect in the simulations so I figured why not. The kit was too expensive for me to pay all at once so I bought everything piece for piece for several places, but no shops in the rip off land of germany.
Then I decided it was time to order the crossover parts, but they were going to cost me over €95. So I started looking around and found a shop that sold the mundorf components and they happened to be €10 cheaper. So I took them. none of the decisive values were different except that the ohm vale of the coils was slightly higher.71 vs. .43 or something. I was told this may reduce the bass response but I'm happy with the bass response so who cares.
I also swapped out the tweeter, since the tweeter that was in the plan is no longer made by peerless. That may or may not have been a mistake, but all in all I'm happy.
The finish is a self sticking plastic foil from DC-Fix. It looks like snake skin and is really beautiful. If that's your thing. we have pretty exotic stuff at our house, so it fits.
Sorry for the long post. But I've been dying to share.
They only had one slanted side and my wife correctly stated that in all likelihood people would think I screwed up if only one side was slanted so I slanted them both. The added volume had a positive effect in the simulations so I figured why not. The kit was too expensive for me to pay all at once so I bought everything piece for piece for several places, but no shops in the rip off land of germany.
Then I decided it was time to order the crossover parts, but they were going to cost me over €95. So I started looking around and found a shop that sold the mundorf components and they happened to be €10 cheaper. So I took them. none of the decisive values were different except that the ohm vale of the coils was slightly higher.71 vs. .43 or something. I was told this may reduce the bass response but I'm happy with the bass response so who cares.
I also swapped out the tweeter, since the tweeter that was in the plan is no longer made by peerless. That may or may not have been a mistake, but all in all I'm happy.
The finish is a self sticking plastic foil from DC-Fix. It looks like snake skin and is really beautiful. If that's your thing. we have pretty exotic stuff at our house, so it fits.
Sorry for the long post. But I've been dying to share.
Final shot of line array dipoles
Here's what I think will be the final location of the BG dipoles with panasonic leaf tweeters, etc. descrbed previously. Not cheap but they blow away anything I've heard in over 35 years of this stuff...
What I've found in this location is that you can literally "walk through" the stereo image... and the image is very stable througout the room. It's almost equivalent to walking around in front of a live concert... the instruments stay put but your perspective on the sound changes. Then, since they're located ~1/2 way in the rrom, you can walk front to back and the band gets closer.. between them it actually sounds like the band is around you... and as you continue towards our front door, the image correctly seems to retreat behind. Wife has heard the same effect. Very unique experience.
Here's what I think will be the final location of the BG dipoles with panasonic leaf tweeters, etc. descrbed previously. Not cheap but they blow away anything I've heard in over 35 years of this stuff...
What I've found in this location is that you can literally "walk through" the stereo image... and the image is very stable througout the room. It's almost equivalent to walking around in front of a live concert... the instruments stay put but your perspective on the sound changes. Then, since they're located ~1/2 way in the rrom, you can walk front to back and the band gets closer.. between them it actually sounds like the band is around you... and as you continue towards our front door, the image correctly seems to retreat behind. Wife has heard the same effect. Very unique experience.
Attachments
>> Do you propose that this effect is caused by the tweeters alone?<<
Not at all.... the leaf tweeter acts only as a front firing"super" tweeter.. with the lions share of the highs handled by 2 Peerless domes firing front and back out of phase (as a dipole). The Bohlender Grabener 75" ribbons are free running from 650 Hz till they crap out at ~ 15 Khz and run as dipoles as well.
It's my opinion that the dipole radiation combined with the room position and the line source behavior of the BG planars are the primary contributions to this effect.
The leaf tweeter simply provides an extraordinarily clean high end. All of the non planar drivers are co-incident with the planar divers within their operating range.
Not at all.... the leaf tweeter acts only as a front firing"super" tweeter.. with the lions share of the highs handled by 2 Peerless domes firing front and back out of phase (as a dipole). The Bohlender Grabener 75" ribbons are free running from 650 Hz till they crap out at ~ 15 Khz and run as dipoles as well.
It's my opinion that the dipole radiation combined with the room position and the line source behavior of the BG planars are the primary contributions to this effect.
The leaf tweeter simply provides an extraordinarily clean high end. All of the non planar drivers are co-incident with the planar divers within their operating range.
Re: Final shot of line array dipoles
Wow, that is almost exactly what I'm trying to build with my second system (for sound reproduction I mean). Those look absolutely awesome
If you don't mind my asking, how much did they set you back to build? (I don't recall seeing you price them anywhere)
Let me get my digital camera from my office one day this week and I'll post my system too.
auplater said:
Wow, that is almost exactly what I'm trying to build with my second system (for sound reproduction I mean). Those look absolutely awesome
If you don't mind my asking, how much did they set you back to build? (I don't recall seeing you price them anywhere)
Let me get my digital camera from my office one day this week and I'll post my system too.
BG Dipoles
Total cost of drivers, xover components, wood, etc. was in the $750 - $800 range for each speaker. Plus quite a few weekends planing cherry, biscuit joining, cutting mdf, etc.... (but that's the fun part, aside from actually hearing the finished hardware)
These roll of rapidly below 50 Hz (by design, because they are augmented by a 5 ft^3 sonotube subwoofer with a 12" titanic, good to ~18 Hz or thereabouts)
You could easily improve the low end for not much more if need be with a different driver complement, but I picked the 6 1/2" Peerless HDS mid subs for their smooth freq. response and taut midbass response. The bass cabinets are tuned to 49 Hz, in a reflex cabinet.
In room spl's at 15 feet measure in excess of 110 dB (wife and kids run from the house!)..sensitivity measures roughly 91 dB @ 1 watt 1 meter, and the sound does indeed fall off at the linesource rate of 1/R rather than inverse square of a point source. You can actually sit within a couple of feet of one speaker and still hear the image and sounds from the opposite speaker. They also fill the entire 2 story space of roughly 15000 cubic feet with prodigious high quality sound.
I've got a second system with very heavily modified (as in all guts, drivers, etc. stripped and replaced and cabinets reinforced) old Infinity RS II's I'm using in my HT setup that is evolving.
Total cost of drivers, xover components, wood, etc. was in the $750 - $800 range for each speaker. Plus quite a few weekends planing cherry, biscuit joining, cutting mdf, etc.... (but that's the fun part, aside from actually hearing the finished hardware)
These roll of rapidly below 50 Hz (by design, because they are augmented by a 5 ft^3 sonotube subwoofer with a 12" titanic, good to ~18 Hz or thereabouts)
You could easily improve the low end for not much more if need be with a different driver complement, but I picked the 6 1/2" Peerless HDS mid subs for their smooth freq. response and taut midbass response. The bass cabinets are tuned to 49 Hz, in a reflex cabinet.
In room spl's at 15 feet measure in excess of 110 dB (wife and kids run from the house!)..sensitivity measures roughly 91 dB @ 1 watt 1 meter, and the sound does indeed fall off at the linesource rate of 1/R rather than inverse square of a point source. You can actually sit within a couple of feet of one speaker and still hear the image and sounds from the opposite speaker. They also fill the entire 2 story space of roughly 15000 cubic feet with prodigious high quality sound.
I've got a second system with very heavily modified (as in all guts, drivers, etc. stripped and replaced and cabinets reinforced) old Infinity RS II's I'm using in my HT setup that is evolving.