Yep. If you are trying to reproduce a short duration sound (a click) and your system produces a longer duration output (the click, then the echo of that click), that is a reduction in fidelity.
I doubt it. Considering how much sound passes through relatively heavy structures (windows, doors and walls), I think a normal loudspeaker cone would be essentially transparent in the 100-500Hz range.
That's a bad news too, isnt it ?
Making an enclosure tight and solid would actually make things worse by activating the acoustic energy bouncing, then pushing it towards the exist (the cone) ?
I just cannot imagine how that sound/noise coming through enclosure bouncing can be positive. But then again, will a massive damping ''kill'' the acoustic energy, somehow ?
Yes, ok, will do it.
I'll epoxy the already-seized VC from the 8FE200 and i'll make some test. I'm too curious to let that pass!
thanks 🙂
no simply shorting the voice coil terminals should suffice in preventing driver excursion at resonance,
the side benefit would be determining if the drivers mechanical compliance has any bearing on the results. loose suspension would allow greater/broader range to be transmitted versus stiffer suspension, no?
a glued up driver would be better as an ashtray...where's my beer...
the side benefit would be determining if the drivers mechanical compliance has any bearing on the results. loose suspension would allow greater/broader range to be transmitted versus stiffer suspension, no?
a glued up driver would be better as an ashtray...where's my beer...
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Theoratically, an ''active'' transducer is not loose. It's ''locked'' in his movement and should be ''seen'' as a moving wall for the internal reflections. Yes it moves, but not at the internal reflections will.
Made a test tonight with a 15PR400 in a small sealed box. Very rigid, 30mm bamboo + 1'' MDF.
First run without anything inside the box.
Then, second run filled with polyester + high density open cell foam + memory foam, in the hope to cover as many frequencies as possible.
Results (to the ears) is the resonances are barely dimmed with the damping.
Of the 3 configurations tested, the best by far is the Open Baffle one. So maybe, after all, that's the solution since it seems difficult to get rid of the resonances.
Of course, i could try to measure the frequency of the resonances, then try to find a material that will damp exactly at that frequency, but i'm not very convinced it would work... 😕
First run without anything inside the box.
Then, second run filled with polyester + high density open cell foam + memory foam, in the hope to cover as many frequencies as possible.
Results (to the ears) is the resonances are barely dimmed with the damping.
Of the 3 configurations tested, the best by far is the Open Baffle one. So maybe, after all, that's the solution since it seems difficult to get rid of the resonances.
Of course, i could try to measure the frequency of the resonances, then try to find a material that will damp exactly at that frequency, but i'm not very convinced it would work... 😕
a shorted voice coil is "locked" electrically hence my referring to it as a "blocked impedance" (i will look for that) part of what we're trying to figure out is kind of like touching an active cone with your finger except in this case the finger is the wave/ pressure from within the box.
can't say that pressure variations due to motion wouldn't change what makes it out, but as a baseline of what gets out thru the cone this is the only static condition i can reasonable conceive of for testing.
perhaps a slow frequency sweep on the driver versus the noise source within the box or vice versa.... empty beer damn it...
can't say that pressure variations due to motion wouldn't change what makes it out, but as a baseline of what gets out thru the cone this is the only static condition i can reasonable conceive of for testing.
perhaps a slow frequency sweep on the driver versus the noise source within the box or vice versa.... empty beer damn it...
that would make the steel ''enclosure'' damn easier to produce 😀
... and that will require subwoofers that can sing even more (read: hellooo W6 series)
The other benefit of OB is that open baffle loudspeakers reproduce bass with less room interaction.
i guess i just got punked by an OB advocate.... where's my bottle of scotch, damnit....
cheers Jon
cheers Jon
http://www.diyaudio.com/forums/multi-way/300713-living-hi-fi-life-120db-per-hour-7.html
Works well on Right channel so far 😀
i guess i just got punked by an OB advocate.... where's my bottle of scotch, damnit....
cheers Jon
Not really a big fan of the OB concept, but i have to admit the 18FH500 works amazingly well that way, much better than in a box (assuming you don't care for the first 2 octaves, of course).
I seriously haven't heard often a drum feel so real, transparent and powerful as i hear it now. 😱
That leads to another question... Uhm, no another thread! haha
Yea, measure it - the worst of it might be outside the 100-500Hz range you were talking about.
The link I gave (post 31) wasn't exactly what you're testing, but he got a ~20dB reduction from fibreglass fill. (See the graph in the section titled "Panel Vibration Damping Experiments").
Actually, Berlin is quite moderate temp. Folks in south-east Europe really have to suffer from temperatures yet unknown in these regions (at some places the lowest reading ever recorded).
Tonight I won't touch the Caol Ila. If any booze at all then only "working class stuff" (cheap chinese Baijiu in this case).
A word from SL on the topic
And a word from me: Some cones are better than others. Today I would use ONLY metal cones.
And a word from me: Some cones are better than others. Today I would use ONLY metal cones.
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