the road i am traveling with my bk-16 backhorn/fe166 combo has lead me to a new topic.
i am finding that ANY amount of stuffing in ANY placement within the horn is causing utter death.
i am thinking now that reducing reflections within the horn is not the way to get optimum sound, smoothness, and life.
perhaps the route is simply to break up standing waves in the enclosure...perhaps even to maximise internal reflections but eliminate standing waves.
fostex hp reflectors?
i would be very interested in hearing from anyone who feels they have tweaked a backhorn with some success.
whip it on me. what, where, how, why?
i am finding that ANY amount of stuffing in ANY placement within the horn is causing utter death.
i am thinking now that reducing reflections within the horn is not the way to get optimum sound, smoothness, and life.
perhaps the route is simply to break up standing waves in the enclosure...perhaps even to maximise internal reflections but eliminate standing waves.
fostex hp reflectors?
i would be very interested in hearing from anyone who feels they have tweaked a backhorn with some success.
whip it on me. what, where, how, why?
You got it Mang! HP diffusors do just what you imagine. They re-direct energy without absorption, allowing it to get down the path and into the room so you can boogie. Just holding one of the lil plastic ******s in the mouth you can hear it's benefit. Sidewall standing waves are causing nulls in the horn. The HP's clean and deepen the bass.
Gonna add me a "noisey" amp to my collection someday, wink nudge.
TC
Gonna add me a "noisey" amp to my collection someday, wink nudge.
TC
noisenyc said:
Check out http://home.hetnet.nl/~geenius/Solo206.html
You can try to cover the magnet with a layer of felt. I don't know if the area of 166 magnet is as large as the 206 but it may be worth a quick try.
Cheers,
Gio.
TC said:
werd!
ima order some of them plastic morning glories and give 'em a try.
makes sense.
no efficiency losses to absorption. how nice.
why take all that nice zingy speaker energy and try to kill it? send it randomly jumping out the horn into my eager ears.
i have noticed an exaggerated breathiness to the driver, and it reminded me of something.
yamaha ns-10's sitting on the meter bridge of every recording studio in america, with a thin layer of toilet paper hanging over the tweeters. the "bob clearmountain" mod.
i will try that too.
re: noisey amp, oh yes there is one in your future.
you raise cain with me, i will make noise at you. say no more, say no more?
HP= Hyperbolic Paraboloid. The concept is the very basis of nearly all Fostex design credo as far as their best efforts are concerned. The flip flop surround as seen on the "e" sigmas, and the spiders. The shape defies resonance pattern amplitude both acoustic and physical. Take a look at the back of the packaging. It shows detailed measurements of the HP diffusors in place and the same speaker without them. It's not the 3db that they shave off peaks that is amazing, or the fundamentals increased. But the resolution of the measurements themselves. They totally make John Atkinsons measurements look positively Boy Scout by comparison.
For me the highlight of CES was the Fostex room. A large (very) studio monitor ($22k) was bi amplified with Accuphase pro amps. Drivers were unobtainium 12"woofer w HP cone, alnico magnet, double damping spider, midrange was HP cone, neodymium magnet and polycast frame with no-spider, tweeter was an unavailable neo magnet alum dome. System was mid 90's efficient with solid bass to 30hz. Cabinet was 3" thick laminated Baltic with iano black. Wired with tungsten wiring (60lb. power cords, 30lb. interconnect) all I can say is we have a lot of catch-up to even begin to learn what the hey Fostex is trying to "say".
Easily the best sound at the show and by a mile. Course not many got to hear these beauties as it was in Madisounds back room, it simply gets overlooked year after year.
TC
For me the highlight of CES was the Fostex room. A large (very) studio monitor ($22k) was bi amplified with Accuphase pro amps. Drivers were unobtainium 12"woofer w HP cone, alnico magnet, double damping spider, midrange was HP cone, neodymium magnet and polycast frame with no-spider, tweeter was an unavailable neo magnet alum dome. System was mid 90's efficient with solid bass to 30hz. Cabinet was 3" thick laminated Baltic with iano black. Wired with tungsten wiring (60lb. power cords, 30lb. interconnect) all I can say is we have a lot of catch-up to even begin to learn what the hey Fostex is trying to "say".
Easily the best sound at the show and by a mile. Course not many got to hear these beauties as it was in Madisounds back room, it simply gets overlooked year after year.
TC
noisenyc said:
He does leave the felt on the back of the magnet.
Can anyone explain why connecting the -ve to the speaker chasis would do anything?
Another idea you can consider is
http://www.diyaudio.com/forums/showthread.php?postid=506477#post506477
Cheers,
Gio.
Re: Re: word to all you backhorn tweakers.
i have grounded speaker frames in guitar amps and gotten rid of some nasty parasitics. i do it routinely in my combo amp builds now.
it only seems effective when the speakers are in close proximity to nasty EMF, transformers in particular...
gmilitano said:
i have grounded speaker frames in guitar amps and gotten rid of some nasty parasitics. i do it routinely in my combo amp builds now.
it only seems effective when the speakers are in close proximity to nasty EMF, transformers in particular...
Hi! I'm the Solo-206 guy!
I found that (as with any loudspeaker design) there are always compromises. With the damping material in and the correction network on I could get a very smooth and polite sounding speaker, nothing wrong with it but also nothing that made my feet move. With most of the damping out and the filter removed they rock! And they also ring like a bell in a small frequency band, most of the time you don't notice it but I have a cd that has a bit of percussion on it and there is one conga that realy "honks" while the rest sound like conga's.
About the grounding of the driver chassis: I guess (but don't have the means to measure it) that some stray energy from the magnet gets lost in the steel chassis and works against the energy in the voice-coil gap? Grounding the chassis drains this stray energy away so that the energy is only concentrated around the magnet pole piece. This may result in my subjective feeling of smoother treble and more punch in the bass. I'm only guessing here, maybe some else has a better idea.
I still have to improve one area and that is the beaming at high frequencies. Off axis they sound very natural and coherent, exactly on-axis they are too "hot". This makes poor quality recordings sound tinny. I can smooth it off a bit with different interlinks, speaker cables and using my KT88's instead of my Vecteur solid state amp, but the bright top-end still remains. I will be experimenting with different types (shapes) of diffusion plugs / phase plugs to try and spread the high frequency energy more evenly in the room.
I found that (as with any loudspeaker design) there are always compromises. With the damping material in and the correction network on I could get a very smooth and polite sounding speaker, nothing wrong with it but also nothing that made my feet move. With most of the damping out and the filter removed they rock! And they also ring like a bell in a small frequency band, most of the time you don't notice it but I have a cd that has a bit of percussion on it and there is one conga that realy "honks" while the rest sound like conga's.
About the grounding of the driver chassis: I guess (but don't have the means to measure it) that some stray energy from the magnet gets lost in the steel chassis and works against the energy in the voice-coil gap? Grounding the chassis drains this stray energy away so that the energy is only concentrated around the magnet pole piece. This may result in my subjective feeling of smoother treble and more punch in the bass. I'm only guessing here, maybe some else has a better idea.
I still have to improve one area and that is the beaming at high frequencies. Off axis they sound very natural and coherent, exactly on-axis they are too "hot". This makes poor quality recordings sound tinny. I can smooth it off a bit with different interlinks, speaker cables and using my KT88's instead of my Vecteur solid state amp, but the bright top-end still remains. I will be experimenting with different types (shapes) of diffusion plugs / phase plugs to try and spread the high frequency energy more evenly in the room.
Super!
I couldn't agree more with noisenyc! Indeed, its been a month or so that I am playing around with my new horn http://audio.dynatech.gr/horny.htm , my findings are exactly the same!
Whatever and in any quantity I add to the backchamber or any part of the horn length, causes the loudspeaker to lose all the energy, sparkling and life ti has without.
The effect is so intense to the point that at the beginning I couldn't believe my ears! Even the addition in the chamber of two small balls the size of pinkpong balls, (made of wool) did cause the loudspeakers to sound like conventional bass reflex boxes.
I am really astonished that my findings are along the same lines of your observations! Keep up the good work!
I couldn't agree more with noisenyc! Indeed, its been a month or so that I am playing around with my new horn http://audio.dynatech.gr/horny.htm , my findings are exactly the same!
Whatever and in any quantity I add to the backchamber or any part of the horn length, causes the loudspeaker to lose all the energy, sparkling and life ti has without.
The effect is so intense to the point that at the beginning I couldn't believe my ears! Even the addition in the chamber of two small balls the size of pinkpong balls, (made of wool) did cause the loudspeakers to sound like conventional bass reflex boxes.
I am really astonished that my findings are along the same lines of your observations! Keep up the good work!
Geenius said:
yes, quite directional. these whizzer cone full rangers sound more extended and more directional to me than many with conventional dust caps or phase plugs.
i see some folks get 'em up to ear level to minimize this which probably works well in larger rooms...to me horns sound better from a distance, more bass and smoother top.
i often design full rangers for near field off axis listening. i picked that trick up from john cockroft who used to write quite a bit about full rangers in tl enclosures for Speaker Builder (see i DO know where the caps key is haha). some day i will scan those articles and put 'em up for y'all to check out. he's a really fun and intuitive hardware hacker.
internal tweaks in this horn seem to really affect the HF sound of the driver, so i'm going to make friends with the cabinet before i do anything else, then perhaps experiment with some fabric dome tweeters in an, uh, unconventional mounting to help the top top top end off axis near field.
i am loath to mod these drivers too much because they are beautifully designed to begin with..yep ima try to finesse 'em first...and let 'em break in...something tell me brute force is the wrong approach for these delicate drivers whose every tiny twitch is magnified by the enclosure and the treatments therein...
step one is to break up peaks and nulls in the midrange within the horn using those fostex HP reflectors which are designed to do just that. nawsty pipe resonances...in straight pipes some simple stuffing serves the purpose well but not in these!
b&w has been doing an "egg crate" style bracing (these are in ported boxes mind you) designed to sort of maximise random reflections, and also break up standing waves and resonances. not a bad idea in horns i think...
anyway it's a slow process, i am busy as hell but i'll post updates as i go.
you really should consider the silicone borscilate stuff..
there is also the tech. some japanese use:
wood charcoal in dissimilar lengths attached to the intereior walls of the compression chamber (I think final labs does this). It acts as both a high freq. absorber and diffusor.
yup, final labs mentions this here (though obviously it isn't for a compression chamber):
http://www.finallab.com/new_page_14.htm
there is also the tech. some japanese use:
wood charcoal in dissimilar lengths attached to the intereior walls of the compression chamber (I think final labs does this). It acts as both a high freq. absorber and diffusor.
yup, final labs mentions this here (though obviously it isn't for a compression chamber):
http://www.finallab.com/new_page_14.htm
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