You can decouple speakers with a suspended spring system. Or you can achieve the same thing with a folded towel, or a few layers of carpet, or a bike inner tube. All perfectly measurable as effective. One costs thousands, the other pennies. You choose.
Anti Vibration Devices
- Thread starter Whizzy
- Start date
Tony L
Administrator
They used this stuff in the early ‘70s! You can see some cables running from the Quad 50E (or may be a 303) on the floor to the Tannoy Lancasters. Proper kit, good enough to record Dark Side Of The Moon!
PS The flip-clock is the important bit. I so need one of those.
NickofWimbledon
pfm Member
They used this stuff in the early ‘70s! You can see some cables running from the Quad 50E (or may be a 303) on the floor to the Tannoy Lancasters. Proper kit, good enough to record Dark Side Of The Moon!
PS The flip-clock is the important bit. I so need one of those.
Now that really is a desk!
Not having 8 other speakers in the room, only 1 ashtray and no coffee stains on the desk already makes that look pretty purist, no?
gustav_errata
pfm Member
Ah so a frequency response can show a speaker's capability (or more often, incapacity) to reproduce a square wave? Because they're all related all you need is one view to tell you everything you need to know, right?
Mildly off topic but indulge me, or ignore me, all good!
I once went for a job interview, the company specialised in seismology instrumentation, sat in their offices near Aldermaston they could see the frequency of the waves lapping on the shore of the UK and earthquakes round the globe ... vibration is an interesting subject, I didn't accept their offer but did go on to work for two more UK manufacturers of vibration monitoring equipment. One of the tools of the trade is an FFT, however you soon learn that while big spectral spikes can tell you a lot, there are other, better ways, of digging out smaller signals from noise. For example ways to find harmonics hidden in the "grass". Stuff you can't see but is there in the data. The audio sweeps REW does are great for comparing roughly in room responses and identifying low frequency modes, but the idea they will tell you definitively if there is any audible change is complete and utter hogwash. It is reasonably hard to get repeatable results from such things, while changing nothing. I don't want to do down REW, it is a great, free, tool. It has its uses. More than I know of I don't doubt. But a spectrum is not the be all and end all of signal analysis, whether vibration (which is broadly the same band) or audio.
I once went for a job interview, the company specialised in seismology instrumentation, sat in their offices near Aldermaston they could see the frequency of the waves lapping on the shore of the UK and earthquakes round the globe ... vibration is an interesting subject, I didn't accept their offer but did go on to work for two more UK manufacturers of vibration monitoring equipment. One of the tools of the trade is an FFT, however you soon learn that while big spectral spikes can tell you a lot, there are other, better ways, of digging out smaller signals from noise. For example ways to find harmonics hidden in the "grass". Stuff you can't see but is there in the data. The audio sweeps REW does are great for comparing roughly in room responses and identifying low frequency modes, but the idea they will tell you definitively if there is any audible change is complete and utter hogwash. It is reasonably hard to get repeatable results from such things, while changing nothing. I don't want to do down REW, it is a great, free, tool. It has its uses. More than I know of I don't doubt. But a spectrum is not the be all and end all of signal analysis, whether vibration (which is broadly the same band) or audio.
sq225917
Bit of this, bit of that
A FR in room just tell you about the accurate FR, including reflections, decay and room modes. A gated FR is better at removing the latter. But ultimately you listen in room, and a simple FR doesn't highlight the difference between a boomy port and a combination of room modes, whereas audibly they're very different things.
No one measurement gives the full picture
No one measurement gives the full picture
awkwardbydesign
Officially Awesome
Not if you make your own!
NickofWimbledon
pfm Member
I will never put my LP12 on anything involving an inner tube made by someone as non-DIY as me- it may be for the brave.
awkwardbydesign
Officially Awesome
I meant the springs, but I tried the inner tube version under electronics and TT; didn't seem to work very well, but I still use them under speakers in the loft system. Stops the neighbours complaining.
John
Rack’em Up!
Why on earth would you want to anyway?
Big Tabs
looking backwards, going forwards
Apple Kart would be okay for a fruit box…
martin clark
pinko bodger
+1: two coupled oscillators with minimal damping are .. an interesting analytical problem. Much, much messier than just one.
iansr
pfm Member
So FR is the only thing that determines the performance of a speaker! Seriously ? You are insulting my intelligence.
cooky1257
pfm Member
Does the logic dictate that these isolation devices effectiveness is level/ amplitude dependant? The little wife friendly boxes that are too popular these days are limited in the energy they can transmit into a room let alone into a suspended floor, drivers with BLs under 10 and most lucky to hit only half of that are really puny impulse devices from the get go so it occurred to me the benefits of these isolation devices will only become apparent at higher sound levels ie higher impulse levels (rather like the difference between hitting a table by dropping a toffee hammer then compare that with a lump hammer.)..so conversely did your non-isolated speakers sound progressively more confused/worse as you increase the volume?
NickofWimbledon
pfm Member
Almost everything here is volume-dependent, isn’t it?
Combined frequency & phase response - then yes (to assessing ability to approximate to a square-wave, which as we all know if usually not very good), at least providing you confine this to modest cone excursion. In a linear system, all you need to know about the time-domain is captured in the freq (+ phase) domain (which I think is what Keith is getting at). I'm not trying to say that you can predict exactly how a speaker will sound from this though.
Speakers are complicated beasts though, unlike an amplifier (where the output voltage is a single time-varying parameter) with a loudspeaker you have to worry about response variation with direction as well.
runforfree69
Spinning vinyl
Money better spent elsewhere I’ve found.