For metal horns, the foil back rubber tapes work well, creating a constrained layer damping [CLD].
GM
For metal horns, the foil back rubber tapes work well, creating a constrained layer damping [CLD].
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
When I first got my A7s used some Dynamat on the horns only to discover that it was not very effective, and expensive to boot! Modeling clay is cheap and very effective, $2 a block at the art school supply store.
I would be incredibly suspicious of anyone that told me roofing tar and felt was "state of the art"
Flex seal is certainly going to add some damping. But for it to be really effective it would have to be pretty thick.
The best combination for woofer flares I have seen is bracing and damping, I have seen sand/epoxy mixtures that worked well.
In the 70's my shop was next to some folks that did "cultured marble", basically a resin concrete composed of marble dust and epoxy. We did a couple sets of horn flares of that stuff, they worked well but added around a hundred pounds to the cabinet. Seemed like a good idea when we were sitting around, let's say "brainstorming", but not practical whatsoever.
Your neighbors called. They like your music.
What if you did alternating layers of seal and playsand? spray a base of seal, liberally dust with sand, let setup then spray, dust, set. repeat as necessary. It may work or be a big mess.
Sonic Barbarian
Originally Posted by Old Guy
I would be incredibly suspicious of anyone that told me roofing tar and felt was "state of the art"
Flex seal is certainly going to add some damping. But for it to be really effective it would have to be pretty thick.
The best combination for woofer flares I have seen is bracing and damping, I have seen sand/epoxy mixtures that worked well.
In the 70's my shop was next to some folks that did "cultured marble", basically a resin concrete composed of marble dust and epoxy. We did a couple sets of horn flares of that stuff, they worked well but added around a hundred pounds to the cabinet. Seemed like a good idea when we were sitting around, let's say "brainstorming", but not practical whatsoever.
I am using a totally stock 825 box, and 100 pounds added was JUST the start for me. I use about 300 pounds of concrete stepping stones on top of my A7-800 825 enclosure and about 60+ pounds on my Emilar EH500 Horn clones ( Showco 9000 ) and about 48 pounds, by ear, was needed on my DIY 12 dB 800 hZ crossover. Over 400 pounds in all. I plan to damp the woofer's curved sides, in the upcoming months. Maybe add a brace ala Bowtie's suggestion. Am open to any and all !! I have recently blocked the bass reflex port, down to maybe 80 inches.
Fun stuff.
LOW OHms....Jeff Medwin
Your experiments with Mass Loading components are all quite interesting Jeff ( even if they are all implemented in a singular downward direction ) .
I imagine it effectively removes an audible form of Acoustic Jitter from your listening experience .
Back in the 50's and 60's it was considered best practice by both Altec & JBL to pot their network components in goop ( & that was a time of tube electronics and EE types needing to find ways to keep B52's and Saturn V rockets flying ) .
- I know of some fellows who follow the "potting" practice but instead use sand to encase their coils & caps ( all to better eliminate micro-tremblors from entering the playback path and causing errors ).
I have here some surplus caps that are encased in epoxy ( made by Real Caps I believe ).
The ringing of horns is easily measurable with today's available tools .
Here are some ( Zilch ) pics showing the ringing of non-terminated ( un-mounted or baffled ) 511 & 811 horns .
With those ( ringing ) resonances just 10-15 db below the fundamental / they will be easily audible ( & annoying ) to the discriminating ear.
The following pic ( an 802D of mine mounted to a cheap plastic horn ) shows less ringing ( there is problem here in that the scaling is different and CSD's display differently from Burst Decay ).
I don't doubt your claimed improvements / though it would be nice to see them quantified at some point .
Many users of the EH500 are quite satisfied ( complacent even ? ) with it's obviously better damped ( less ringing ) performance ( I count myself in that group ) .
It seems ( anecdotally ) that the rest of us consider "clean" to equate to keeping resonances at a mere 20-30 db below the fundamental .
Maybe someone can dig up a AES paper on this to support my conjecture ( Mah ? )
It would be instructive ( for the rest-of-us ) to get a base line showing the ringing profile of a EH500's ( before & after some Mass Loading of say, 10lb increments ) .
It would also be instructive ( to the rest of us ) to know what your satisfaction metric equates to ( ie; Ringing/Jitter that is 30 or 40 , maybe even 50 db below the fundamental ?? )
best <>
Last edited by Earl K; July 16th, 2017 at 12:09 PM.
Quite a bit of difference. In my case the 100 pounds was added directly to the horn flares, in addition to the flares being composed of an inherently non resonant material. The mass was added at the point of origin {the woofer} vs elsewhere. A surgical rather than sledgehammer approach.
Your neighbors called. They like your music.
No doubt. Liked your post. What I did is benign, totally reverseable, and leaves the 825 box totally stock. I WILL make permanent 825 changes over time, but there are many other parts of the SYSTEM, I want to optimize, performance - wise, first. Amps are the biggest area that need huge gains and careful thought and attention, ( IME, IMHO ), followed by internal wiring, DIY crossovers, Attenuators, and Sources to feed the A7-800s.
Thanks for posting.
LOW OHMS.....Jeff Medwin
- - - Updated - - -
Hi,Your experiments with Mass Loading components are all quite interesting Jeff ( even if they are all implemented in a singular downward direction ) .
I imagine it effectively removes an audible form of Acoustic Jitter from your listening experience .
Back in the 50's and 60's it was considered best practice by both Altec & JBL to pot their network components in goop ( & that was a time of tube electronics and EE types needing to find ways to keep B52's and Saturn V rockets flying ) .
- I know of some fellows who follow the "potting" practice but instead use sand to encase their coils & caps ( all to better eliminate micro-tremblors from entering the playback path and causing errors ).
I have here some surplus caps that are encased in epoxy ( made by Real Caps I believe ).
The ringing of horns is easily measurable with today's available tools .
Here are some ( Zilch ) pics showing the ringing of non-terminated ( un-mounted or baffled ) 511 & 811 horns .
With those ( ringing ) resonances just 10-15 db below the fundamental / they will be easily audible ( & annoying ) to the discriminating ear.
The following pic ( an 802D of mine mounted to a cheap plastic horn ) shows less ringing ( there is problem here in that the scaling is different and CSD's display differently from Burst Decay ).
I don't doubt your claimed improvements / though it would be nice to see them quantified at some point .
Many users of the EH500 are quite satisfied ( complacent even ? ) with it's obviously better damped ( less ringing ) performance ( I count myself in that group ) .
It seems ( anecdotally ) that the rest of us consider "clean" to equate to keeping resonances at a mere 20-30 db below the fundamental .
Maybe someone can dig up a AES paper on this to support my conjecture ( Mah ? )
It would be instructive ( for the rest-of-us ) to get a base line showing the ringing profile of a EH500's ( before & after some Mass Loading of say, 10lb increments ) .
It would also be instructive ( to the rest of us ) to know what your satisfaction metric equates to ( ie; Ringing/Jitter that is 30 or 40 , maybe even 50 db below the fundamental ?? )
best <>
I just added weight by ear, using music play-back, until I no longer feel there is a gain to be had, that is worth any extra mass being added.
The whole result is a function of the SYSTEM, which includes the amps, specialized internal wiring, attenuator, crossover and parts and my own DIY executions of same. I take my time, slow and deliberate, and always A-B to make final determinations. FUN !!
Jeff Medwin .... Low Ohms.
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