Do IsoAcoustics products affect dispersion?

[Thomas_A]

The effect of the different placement is obviously there but besides that they indeed reduce the vibration emitted by the speakers. Such effect can be perceived. Genelec which is known for not doing nonsense delivers its speaker with a rubber like stand which handles the same issue.

Exactly. Genelec know what they are doing.

 

[Thomas_A]

An extreme example, but shows the principle

 

[zeppzeppzepp]

I have one of their product.
It really depends on the need for isolation between loudspeaker and the surface it sits on.
Rubber or similar material surely absorbs some sort of vibration.
I'll say maybe good result will occur when loudspeaker with very solid enclosure sitting on something hollow like desktop.
But if the loudspeaker's enclosure is more resonant, the isolation feet will change the tonal character often not in a good way.

 

[Matias]

Here is a test and recording with the speaker at the same height. Listen with good headphones.

 

[Thomas_A]

Here is another listening test

Hard vs soft speaker feet:

https://www.dropbox.com/s/yuozsq6dx1f3ybc/hard vs soft feet.wav?dl=0

It's an easy one to detect.

 

[Longshan]

Next time give your money to a charity or directly to a homeless person.

 

[pos]

Here is a test and recording with the speaker at the same height. Listen with good headphones.

I don't get exactly what he is doing there.
Is he playing both speakers simultaneously, one with isoacoustics and one with spikes, recording simulteanously with (stereo??) canon mics pointing each speaker, soloing each mic in turn?
That does not sound right...

 

[Matias]

I don't get exactly what he is doing there.
Is he playing both speakers simultaneously, one with isoacoustics and one with spikes, recording simulteanously with (stereo??) canon mics pointing each speaker, soloing each mic in turn?
That does not sound right...

He pointed one mic into each speaker and recorded stereo each time, before both speakers with regular spikes, and after both speakers with the Gaia feet.

 

[pos]

Ok that makes more sense.
I listened to the comparison without knowing which was which, on purpose, and it turned out I "prefer" the one with the spikes :/

 

[Thomas_A]

Ok that makes more sense.
I listened to the comparison without knowing which was which, on purpose, and it turned out I "prefer" the one with the spikes :/

If you listen to my short sweeps do you still prefer ”spikes”?

 

[Matias]

Ok that makes more sense.
I listened to the comparison without knowing which was which, on purpose, and it turned out I "prefer" the one with the spikes :/

But how do you know which recording is which feet? As far as I know he has not told the results. The point of the video I think was to blind test the audience and show that both sound different even at the same height.

 

[617]

There are 2 sorts of isolation that get used, one is pukka isolation, where the mass of the object is suspended on a low damping elastic element, with these everything above about 2x the resonant frequency of the mass on the elastic element won't get through.
The other is absorption, where a lossy material is used between the items. Here the vibration is converted to heat in the lossy material, it is cheaper but variable in its frequency effectiveness abd does not usually absorb very well at low frequencies.
A rough rule of thumb is that an isolator which isolates over the full audio range will deflect about 1" when the mass of the object to be isolated is placed on it. If it deflects less it will be isolating from a higher frequency (¼" is probably fine for little desk speakers).

Edit, I forgot the fact that, if you don't isolate your desk top will be behaving like the sound board of a piano and the sound will certainly not be accurate.

Can you provide more information on 'pukka' isolation? I searched for it and I couldn't come up with any references to that.

 

[pos]

But how do you know which recording is which feet? As far as I know he has not told the results.

Yes he does, around 1'25" (don't want to write which it is here, in case anyone else also wants to do the test "blind")

 

[pos]

If you listen to my short sweeps do you still prefer ”spikes”?

I'd love to see measurements, but please do no make me listen to sweeps

 

[Thomas_A]

Can you provide more information on 'pukka' isolation? I searched for it and I couldn't come up with any references to that.

Similar soft feet information, available for around 30 years or so. One of many isolators.

http://www.sonicdesign.co.uk/info.htm

 

[Thomas_A]

I'd love to see measurements, but please do no make me listen to sweeps

Its not that bad, this time. Try it. Distortion plots are linked a few posts up.

 

[Frank Dernie]

Can you provide more information on 'pukka' isolation? I searched for it and I couldn't come up with any references to that.

Pukka is English slang for real or proper, sorry it doesn't translate for a world audience.

 

[Kachda]

Pukka is English slang for real or proper, sorry it doesn't translate for a world audience.

Actually pukka comes from hindi/urdu and the British started using it during colonial times

 

[Frank Dernie]

Actually pukka comes from hindi/urdu and the British started using it during colonial times

I know the origin. In English it is slang though.

Edit and I would say it is southern English slang too - anybody correct me if i am wrong - I have not heard it used in Scotland or Wales.

 

[617]

I know the origin. In English it is slang though.

Thanks, Frank. If I'm understanding you correctly; if you suspend a vibrating thing on a spring of some kind, everything above 2x the resonant frequency of that system will be uncoupled at that interface? So, for example a speaker on an elastic stand of some kind will prevent those frequencies from reaching the floor, and vice versa, but the sound of the speaker's radiation won't be changed significantly?

This seems to bear out the common assertion that the only effective damping for low frequencies in rooms is flexible walls.

I went to architecture school, so my understanding of physics doesn't extend much past statics which are of course not useful in audio.