Yes, I agree with this. If the DI is high and the speakers toed in the imaging can be excellent without wall treatment. I do that.
I don't know what you mean by "periods" for the time axis, but the way this is displayed is normal for waterfalls.
A decay waterfall with periods instead of msec, is a pretty simple transform, and with all the talk of measurements you don’t know? 35-40 dB is more useful.
Also called burst decay. This is an example from @Joseph Crowe site. Toole gives a good explanation why this formatis better.
One can directly comoare the Qs of resonances, and it makes it easy to read the ring down. A good ring-down has nice parallelism curve.
dave
Also called burst decay. This is an example from @Joseph Crowe site. Toole gives a good explanation why this formatis better.
One can directly comoare the Qs of resonances, and it makes it easy to read the ring down. A good ring-down has nice parallelism curve.
dave
I don't understand the hassle - there are products out there for decoupling loads. No, not these HiFi stupidities, proper vibration decoupling.
Search for Sylomer pads. Cheap and easy to use. Choose the right ones for your weight and you are done. (Sorry wrong country. But they are available world wide ;-), took 1 minute)
https://www.spillner-ssb.de/sylomer/pads.html
https://www.amazon.de/PolySound-Hig...ungsdämpfer-23-60kg-braun/dp/B07NLDJ8HM/?th=1
You get a resonance frequency 11-14Hz, that's pretty good for such an easy and cheap tool.
When you need BETTER - it get's way more complicated. Pure spring loaded decoupling gets very weak/wobbly with the usual loads and very low resonance frequency. Air decouplers would work down in the 5Hz area but are a hassle and pretty expensive. You have to maintain the pressure or get some permanently connected to the air pressure network - which you normally don't have in private houses ;-)
p.s.: a decoupling mechanism ALWAYS has to work with the load/weight! When there is no component weight specified - forget it, it's 100% to stiff.
The hassle is isolation is dismissed in principle, regardless of effectiveness, cost or fashion. Unless it's a refrigerator. Maybe.
Depends on the use case. I decoupled my woofer array which is mounted on the wall to get less vibrations in the house structure. Decoupled my turntable which helped significant. And did NOT decouple my refrigerator cause it's a modern, useful model 🤓
Regardless what you do (coupling or decoupling) - weight is your friend.
Until you do subwoofers, then stiffness is your friend. 😎
My experience with a number of large DIY subs, is that stiffness has mainly helped milking all the SPL I can get out of the sub.
And that it doesn't really effect how much a sub vibrates.
I think because the most obvious vibration from a sub, comes from asymmetric motor excursions...transient hits that make the sub want to jump or walk around. Heavy prosound motors can really hop.
I sometimes speculate that less stiff might absorb some of the asymmetric motor hit, reducing the walk around factor. But dunno at all, never tested the wacked out idea.
And yes for sure..... weight is indeed our friend. Or use double opposed to cancel asymmetric transients. Or bolt the dang subs to the floor ! 😀
2 kinds of vibration - don't mix them up.
Panel vibration. (cabinet vibration) Make a stiff panel with it's resonances outside of the woofer range - no panel vibrations!
"The whole woofer jumparound vibration". (we need a more scientific word for that). Therefore you need weight compared to the membrane weight + acceleration. Just put a few concrete/stone plates on top if the woofer itself got too light.
Opposed drivers help a lot with that! It's a pretty good concept and also can help with room acoustics when done right. (HiFi, not PA).
But when your panels are so weak that it cancels membrane/woofer movements ... you build an instrument, not a speaker.
Panel vibration. (cabinet vibration) Make a stiff panel with it's resonances outside of the woofer range - no panel vibrations!
"The whole woofer jumparound vibration". (we need a more scientific word for that). Therefore you need weight compared to the membrane weight + acceleration. Just put a few concrete/stone plates on top if the woofer itself got too light.
Opposed drivers help a lot with that! It's a pretty good concept and also can help with room acoustics when done right. (HiFi, not PA).
But when your panels are so weak that it cancels membrane/woofer movements ... you build an instrument, not a speaker.
Yep, agreed. I wasn't mixing them up, at least in my mind. Sorry if it didn't read that way..
For me, sub vibration equals walking because I almost never let subs run above a steep 120Hz crossover.....so there are no panel vibrations to excite with resonance.
That said, one very large 750L dual 18" reflex had internal dimensions long enough, that it did take additional bracing to tame resonances that occured in the sub's pass band.
Yep, maybe a more scientific term would help.... Or I should just stick to the well known descriptor..."sub wants to walk". 🙂
I don't think membrane weight, or the air being pushed by the membrane, is what causes the asymmetric inertia / walking force.
I think it's the weight of the motor / voice coil assy. 300+ gram motors are quite common in prosound sub drivers. Lot of weight to throw around.