Yes indeed..... I sprung for a sheet of that expensive stuff to try out on my go-to favorite CD/horn combo, a 4594/1464.
Can't say I heard anything other than a HF attenuation...a disappointment really...
Yes, sorry for not including that.....
I did compensate, even to the point of generating new FIR files from the attenuated measurements.
The method I'd suggest is to, start without foam and turn it up until it drills your skull (ie the diffraction sets an upper limit in level). Then add the foam and see if you can take it further.
If you EQ'd, and you still heard a HF loss, doesn't that imply less ringing and such in the attenuated region, as less energy over time would sound like less HF even when EQ'd.
IOW, I'd say, a flat FR that sounds quieter at HFs than a similar device with the same FR is probably performing better.
I've clearly done a bad job of explaining....
Started with a speaker that had been tuned ruler flat mag and phase.
When I added the special foam to the horn, a HF attenuation was obvious.
With foam in place, I re-tuned to ruler flat.
Sounded just like speaker without foam...no subtle improvements that I could hear...
May repeat the test sometime at high volume outdoors...give it another chance...
The foam plug is controversial...
If you have made a fair a/b test of a horn with and without the foam mod, assuming the frequency EQ has been made similar in both, and
You can't hear any difference, then before you say the foam mod makes no difference, it could be because your horn is flawless even without foam
If you have made a fair a/b test of a horn with and without the foam mod, assuming the frequency EQ has been made similar in both, and
You can't hear any difference, then before you say the foam mod makes no difference, it could be because your horn is flawless even without foam
Indeed! Do the foam test with one of these once coveted horns [and still are by the Altec 'faithful'] and can't tell a major difference is a strong indication of severe hearing impairment: https://images.reverb.com/image/upl...90,w_620/v1502512789/icmu8s1kbp3qonjw3f52.jpg
Sadly, no amount of internal damping can solve its myriad problems that require driver/throat matching, cutting out the vane welds and replacing with some form of viscous damping, external bell damping, removing internal brace, sealing the internal surfaces and finish off with a large foam mouth extension/baffle.
GM
I truly hope no one took my single 4594/1464 experiment, to mean I was implying HOMs aren't a real problem...
What I meant was, I was bummed not to hear an improvement...
Aren't we always happy to find something that clearly helps our sound?
I took the lack of noticeable improvement to mean the horn is already pretty good
What I meant was, I was bummed not to hear an improvement...
Aren't we always happy to find something that clearly helps our sound?
I took the lack of noticeable improvement to mean the horn is already pretty good
In one respect, anyway.I took the lack of noticeable improvement to mean the horn is already pretty good
I easily agree with what you guys are saying, particularly with the difficulty of short term evaluations .
In fact, I barely do any form of A/B testing anymore...just too much bias and stored up preferences.
So, after I setup tuning for any new design/modification, I will listen for at least a day or two, on and off, all kinds of different music, ....unless I clearly screwed the pooch.
Since I no longer care about sweet spot tuning, listening occurs all over the place, including adjacent rooms.
After a while, I'll either be finding things that don't sound quite right, or be saying to myself "damn, that sounds really good".
When it passes the 'sounds really good test', I wait for the chance to listen outdoors where reality gets quite a bit clearer.
In fact, I barely do any form of A/B testing anymore...just too much bias and stored up preferences.
So, after I setup tuning for any new design/modification, I will listen for at least a day or two, on and off, all kinds of different music, ....unless I clearly screwed the pooch.
Since I no longer care about sweet spot tuning, listening occurs all over the place, including adjacent rooms.
After a while, I'll either be finding things that don't sound quite right, or be saying to myself "damn, that sounds really good".
When it passes the 'sounds really good test', I wait for the chance to listen outdoors where reality gets quite a bit clearer.
Well a poorly designed speaker would be objectionable upon first listen but what I’m referring to is a loudspeaker that initially sounds fine/good/great/wonderful but causes physiological discomfort after more than a few hours. Like the firmware in our heads has become fatigued from an unconscious signal recovery process.
I imagine a way to test for this is to have two sets of speakers where the only difference is one employs a hypothetical HOM-reduction procedure (ie foam) and long listening sessions are incentivised. With a large enough sample group, one could look for evidence of a trend of longer listening sessions with the treated speakers vs the untreated.
I imagine a way to test for this is to have two sets of speakers where the only difference is one employs a hypothetical HOM-reduction procedure (ie foam) and long listening sessions are incentivised. With a large enough sample group, one could look for evidence of a trend of longer listening sessions with the treated speakers vs the untreated.
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