Case in point. We're far from an ideal measurement scenario, in particular with free standing speakers with fairly different designs and directivity.

Look at SBIR factor for ex.

We designed quite a few test rooms for speaker and audio manufacturers, including anechoic. The data issued from measurements in the room on the photo is not to be considered reliable or useful.

Change environment and see the graphs change dramatically.

On the other hand. For me, personally, it's more interesting to see measurements from well implemented real world scenarios than anechoic chambers. In the real world we have off axis radiation and room influences, and this aspect is also part of what the speaker design has to cope with. We can't solely consider the direct response. It is in fact the differences in dispersion among other things I am very interested in.

As you say, it's far from an ideal measuring scenario, but only if it's pure on axis frequency/phase response that your'e after. Well, thats not what I'm after.

The interesting bit here is that Audiovisjon has measured many different speakers in roughly the same spot, and in the same, seemingly well behaved room. That gives us some point of reference. It's not like that floor, or those walls all of a sudden decided to reflect in a different manner between measurements.

I am not trying to take away from the facts that you presented, just delivering a different perspective.

Smart phones are not reliable for this (imprecise) and conditions in the test room must be controlled (external vibrations from foundation etc.).

My point here is not to say which speaker is better. But it seems the speakers tested have very different dispersion - Amphion talking about their U/D/D technology (uniformly directive dispersion) but I can't find a single graph of it's behaviour or clear official explanation of it so far.

If it's anything like Geithan speakers, then within Audiovisjon's room it has a major impact and you can indeed consider that boundaries start to reflect in a different manner because they're interacting with the speakers in a different way.

That one enjoys brand / model A over brand / model B in a certain environment - sure, no problem.

But using a flawed measurement method to try and prove a point or "fact" that just isn't there is a very different thing.

It is likely that all high end speakers measured except those using Transmission Line that will clearly show a 90° phase shift somewhere down in the LF (IIRC) will exhibit fairly similar phase responses if measured in a proper lab.

Kind regards,

No doubt there is much more accurate test equipment but that's not going to happen. And my test room is my studio it's the only test room I care about , and it is what it is. Which is in fact in an attic and is in reality the third story in the building.
The only test that matters to me is how "much better" (according to you) sorbothane pads measure out than the ISO Acoustics stands with an I phone app, at isolating the vibration on the speaker plate on the Sound Anchor stands in the situation I am in, not some situation I am not in.
And what ever amount an I phone app might actually be imprecise by, is not going to change between the sorbothane and ISO Acoustics
So it will either measure out as "much better" or it won't, in my studio with an I phone app. Since I don't think it fair to keep side tracking the OP I'll make this my END OF STORY

I can agree to a certain extent. There is a definitive cap on what readouts you can do from Audiovisjon's data.

But I like how you can compare the rate of phase shift and stereo phase uniformity from the measurements. I trust that Audiovisjon made proper preparations with measuring distances from speakers to mic etc. Some speakers clearly have differences in phase response within the pair tested, and others have a close to perfect match. Further on, the rate of shift presented in say the Mayer speakers make me wonder just how cohesive they can actually sound. The phase shift of the Amphions is, if not the smoothest/calmest in the test, at least at a shared first place with the Geithains and the AML1's.

The CDD "technology" is, as I have understood, simply the use of wave guide controlled dispersion of the tweeter to match the woofers dispersion, which makes off-axis FR nice and even throughout the frequency range, which in turn make them sound nice even in compromised rooms.

So not an equivalent to Geithains cardeoid response. Simply the good old "constant directivity" principle.

wow, so in your room, the one18 are basically flat down to 40hz?!

do you have a lot of bass traps and treatment in your room? how big is your room?

Yeah. I feel I get useful information down below 40 actually. It's a small room of 2,85/3,85/2,50 meters W/L/H. I got massive, thick porous first reflection absorbers across the walls from floor to cieling, and across the cieling. Thats it, hence the peaky modes you can see below 100 hz.

The rest of the treatment are just in the starting gates.

Small room plan - what do you think? Opinions wanted!

I have got a pretty flat bass from 30 hz without eq on the one18.

My visitors keep asking about the speakers. I tell them shhhh, don't ask. No regrets, I love these monitors.

3 questions!

1) How well do the Amphions (One18 in particular) work in untreated rooms? I'm a mere hobbyist and currently can't afford a separate studio room, so I make my music in the living room. That will change, but not in the near future unfortunately.

2) How well do the Amhions work when you just listen to music (sometimes music that is quite lofi too) for pleasure? I know some monitors (Genelecs particularly, at least IMO) are great as studio monitors but fail when you want to just listen and enjoy music, because they easily fatigue the ear, at least my ear.

3) I make mostly late 80's and early 90's inspired electronic club music (ie. quite rough stuff and definitely not produced to modern standards). How well do the Amphions work in that context? I know, good monitors work well with any kind of music, but I'm still wondering if the Amphions would be the best choice for me or is there something even better in the price range.



I'm from Finland, so testing them myself is very easy. I just like asking 2nd opinions!

Results with poor equipment could be misleading and environment must be without external or internal vibrations, which could change any time + low frequency "little" deviations you can not feel easily physical (by body) but could change the results.
Try and report and you will se what you get

I concur. ISO Acoustics stands do not perform. And I cannot see how they could perform either. One could set his nearfield speakers on 3-4 half tennis balls and get better results.

My colleague Silvia and I had a close look at them at AES and spoke to the team on the booth. They had no idea what "Natural Frequency" or "dependency on amplitude" meant and could not give us any rough number. Yay!

After a 2 minutes discussion the rep pretty much walked away.

Their website talks of a test. But it gives neither the results nor any other useful information.

For such a lightweight system to work in particular at low frequencies where 90% of the mechanical coupling problems are, the static load being basically non-existent the whole stand would have to be a lot softer and hence wobbly. To the point of being unusable in a studio. Or you'd have to increase the static load dramatically to then allow higher system stiffness.

We regularly build very low natural frequency (<5Hz) custom decoupling systems for main speakers that are sometimes installed... In glass. To get it to work requires tuning, heavy dummy counter loads, custom industrial parts like high quality springs and pre-constrained high pressure dampers. It's not straightforward at all.

For a 73kg / 160lbs Speaker (ATC 110) added pressure on the decoupling system via the dummy loads is around 300kg / 660lbs in the Z axis and 180kg / 396lbs in both the X and Y axis. We're almost at a factor of 10.

It's very far from a bunch of plastic tubes and rubber pads.

What if I told you that I use isoacoustic stands and the sound improved for me ?

I would believe you.

But the improvement would certainly not be from LF decoupling:

- Difference in speaker height and angle (can make a substantial difference especially wrt to ear Pinna response -HRTF- and interaction of sound with workstation desk surface)

- Small incremental difference due to a bit less HF & HMF vibrations reaching speaker stand or desk slightly improving overall clarity

- Other, quite possibly negative, impact of the ISO Acoustics stands such as likely enhancing transmission of lower mid frequencies to speaker stands or desk, but perceived by users as a positive result just because it creates an audible difference (more forward low-mids for example).

And last but not least:

- Psychological, expectation bias.

Kind regards,

Mastering engineer for EA Sport’s Madden NFL16 reveals his winning formula!

"Since the first time I worked with them I knew that I couldn't imagine a single day of mixing without the Two18’s, and thankfully I haven’t had to. They’ve redefined the art form and rekindled why I fell in love with this craft. Definitely a “pry from my cold dead hands” sort of thing and I couldn't be more grateful about it. Thank you Amphion."

Maged Ragab (X:144) is a producer, mix & mastering engineer, who credits include Ms. Lauryn Hill, Qusai, EA Sports, Madden NFL 16.

www.x144.com

dB

==

So what were the measured differences in decoupling between 1/2 tennis balls and ISO acoustic stands ?

At constant load (speaker weight) Tennis balls will have a higher deflection (softness) and better bounce up = better performance. So I already know who's winning.

But let's do a rough run of the numbers so you have a better idea of what's going on.

First you must calculate the stiffness of the decoupling (elastic) layer. For that you use the equation s= ES/d where E is the elasticity modulus (Young's modulus) S the surface and d the thickness.

Half A tennis ball being fairly softer/ more elastic than the Iso Acoustics stand with less contact surface (just tip of the half balls) and the interface can be considered to have more more thickness you necessarily get s (tennis ball) < s (Iso Acoustics stand).

Which means the 3 half tennis balls are less stiff than one ISO Acoustics stand. That's a clear hint at better performance already.

From there we can calculate the resonant (or natural) frequency of the system which is:

f(0)= (1/2Pi)sqrt(ES/Md) with M the total mass (here, speakers).

The Mass M being a constant (speakers) only the stiffness s we calculated higher matters.

Since we know the factor s for the half tennis balls was lower, it mathematically implies that the natural frequency for the tennis ball will be lower.

Which means the half tennis balls start decoupling from a lower frequency, calculated at f(e)=sqrt(2)xf(0).

Tennis balls are more efficient.

I'll happily run an accelerometer test if any ISO Acoustics stands user can lend me stands for a couple days. But I have little doubt as to the outcome.

One of the other factors that also must be taken in account in calculating such systems is called "Foundation Compliance" (Impedance, mass, spring characteristics, insertion loss etc) and will dictate if the support on which the decoupling interface is resting (stands or a table top / furniture) will in fact increase or decrease performance of the decoupling system itself.

Ideally you want your support/foundation as heavy and stiff as possible.

All that to say "I have not measured the difference between 1/2 T balls and ISO's " The rest is interesting but, what one might call expectation bias . :
I will go ahead and run my own tests and maybe even report back, but not in this thread as this is not an ISO Acoustics thread, it's an Amphion Speaker thread.

All this to say in this case I don't even need to test to know.

Your test is like saying "I'll test frisbees instead of wheels on my car and report back because I don't trust your maths".

Expectation bias?

Are you of the opinion that the sorbothane discs are effective decouplers and isolators from vibration?

What do you think of the very expensive solutions found in Audiophile World? People are spending $$ thousands $$ on products such as Stillpoints and Nordost Sort Cones. Are inexpensive solutions just as effective?

I'm on a solid cement slab, so I'm not too concerned about vibrations there, but I do wonder about vibrations from the amphion Baseone 25 into the monitors sitting on top. Certainly, it seems something should be between the Base and Monitors to isolate the two.

Suggestions anyone?

[QUOTE] there ya go Expectation bias?


OK So that's a "YES I HAVE NOT MEASURED" glad we got that settled. Your hilarious juvenile attempt to insult my testing is rife with irony, given my test will be based on the criteria you yourself laid out I'll happily run an accelerometer and Ideally you want your support/foundation as heavy and stiff as possible. Since you in fact have not actually measured .... Your math may be correct but it is based on assumption not actual measurements. So YES correct I do not trust "your" "maths".

KevWind, When you do some testing and start a new thread, please post the new location there so we know when and where to look for it.

Yes I'll do that

I ran the simple maths based on a fact, not an opinion or assumption.

Although I'm pretty sure that overall half Tennis Balls would perform poorly too, especially compared to purpose designed materials like Sylomer, Regufoam, Sorbothane and dedicated spring+damper.

I'm glad you find this funny.

There is nothing juvenile in trying to show you that you can have a reliable answer performing simple calculations, without needing to perform a questionable test with inappropriate tools.

Next time you drive over a bridge, most of them use dampers and deck decouplers (as on photos). Calculations are obviously way more complex but the basic principles remain.

But wait, this is all based on wild assumptions! Don't trust 'their maths' and get your i-phone accelerometer out. Or maybe just swim across?

Kind regards,

Sorbothane discs & hemispheres are pretty good. Make sure you get the correct durometer and load over them. It's cheap and will greatly exceed the performances of all audiophile cones, spikes etc.

Sylomer is another option and works really well - we use it all the time.

A good way to increase performance is to increase static load on the pads. This is easily done by adding a 4" / 10cm thick blue stone (for ex) cut to the size of the speaker between the speaker and the pads. Then match the pads to the load. You can cover the top of the stone with adhesive 4mm neoprene. Al this is cheap to get.

It's best to slightly exceed by 5-10% the maximum static load recommended for the pads and compensate for the fact that speakers are front heavy due to drivers by offsetting the rear pads a bit towards the front to balance the load repartition. Or use 2 pads in the front and one in the back. This decision is to be taken based on how much extra weight is added with the stone vs speaker weight.

Pretty long off topic....... I still like my IsoAcoustic 200's, also based on them getting the speakers into the right position in my room, not just their isolation performance. But hey, why not start a thread about it, chaps....

I find it way funny . That calculations are used in engineering is not news. The funny irony again is of course the calculations that go into engineering a bridge are based on all ready having the pertinent measured numbers for pertinent factors inherent in the materials to be used, having already been measured for the criteria necessary to plug into the calculations.
They are not based on things like "Tennis balls will have a higher deflection (softness) " which sounds reasonable but having not actually been measured is still an assumption. So your bridge analogy doesn't really apply.
And to clarify what is juvenile in your replies is not what your saying about calculations etc., it is your attempt at smart ass insults incorporated into your replies that is clearly a juvenile response tactic. Loose that s**t and perhaps we can discuss otherwise we are done. "Kind regards" back at ya.

My thoughts exactly and god save us from self anointed smart A experts.

We know a<b and this is all we need to know to get the answer in terms of performance ranking. I'll leave the discussion here.

Northward Acoustics