I am lost in all this translation
My room is all that matters as well as anyone elses room
Is it not in room measurements that dictate the final outcome
who lives in in a chamber?
A chamber is only a yard stick
That is true. And everyone's room is different. So to compare DUT the room needs to be removed.
dave
dave
so if i take the best measuring speaker on the planet and plonk it in my room
That would be a worthless excercise😉
but if i take any speaker
and measure it from my listening position that would be worth while😉
and that could in then turn be the best speaker on the planet😕
the mind boggles
That has nothing to do with the definition of power response.
Every loudspeaker is affected by the room it is put in. But to compare a measurement, that measurement needs to be under the same conditions for each speaker and independent of outside influences.
You can then, ideally, look at that power response and, knowing your room, have an idea of how your room will modify your response.
dave
Every loudspeaker is affected by the room it is put in. But to compare a measurement, that measurement needs to be under the same conditions for each speaker and independent of outside influences.
You can then, ideally, look at that power response and, knowing your room, have an idea of how your room will modify your response.
dave
If it was that simple😀
The yardstick is the response companies provide (which we rely upon as consumers)
But how many companies manipulate that yardstick
And how many are using EQ to optimize the results
Not to mention the levels of smoothness in graphs
Putting it another way, if you build a speaker that has a flat on-axis response in an anechoic chamber, you can then gauge how a room affects it's emission by the time the sound gets to your ear? Well, not quite. If you measure the "power response" of a speaker in an anechoic chamber (graphs of every angle on all 3 axis), then you can gauge how the room will affect it's emissions significantly better. On axis response alone is useful info, but not the whole story. Low frequencies diffract and are largely omni directional (unless is dipole or bipole - in which case they largely cancel at the sides because of the diffraction), and higher frequencies are more unidirectional, so the polar patterns come into play when the speaker is taken out of the anechoic chamber.
Having said all of that, who has an anechoic chamber and the test equipment to do a good "power response" test? Not many DIYers. But understanding the concepts is useful. Then you can do a reasonable job of guessing how a speaker will be affected by a room.
Having said all of that, who has an anechoic chamber and the test equipment to do a good "power response" test? Not many DIYers. But understanding the concepts is useful. Then you can do a reasonable job of guessing how a speaker will be affected by a room.
You can measure the power response of a speaker (anechoic or gated will do), or the in room power response. Above the schroeder frequency I think it makes more sense to measure the speaker power, and aim to keep it balanced within the room using acoustic means.
Below this frequency the measurements should be in room as the interaction is inevitable.
As you say, FR and power don't always match. The fix is acoustic control (there are other means, eg the way it is done within a crossover), for example the simplest way is to measure power and from all the angular measurements you took, choose one that most closely matches the balance of the power plot.
Below this frequency the measurements should be in room as the interaction is inevitable.
As you say, FR and power don't always match. The fix is acoustic control (there are other means, eg the way it is done within a crossover), for example the simplest way is to measure power and from all the angular measurements you took, choose one that most closely matches the balance of the power plot.
Probably 😉 . Unless it measures well to suit such a room and is used as designed.
If you took a random speaker and were told you couldn't move it, then yes it would be a worthwhile excercise.
Otherwise you are just equalising room issues.
This may have already been answered, but this indeed is the audio-industry-standard allocation and labeling of the c.-10-octave range of human audibility--3 octaves of bass, 4 of midrange, and 3 of treble.
If you meant 'human voice' instead of 'human', you're correct, but the industry's products are expected to cover the vast majority of the audible range of 20Hz - 20KHz.
Well, the classic two-way horn systems (Altec, JBL, Augspurger, etc.) typically use a 15" LF driver crossed over somewhere between 500 and 800 Hz or, in the case of Tannoy dual concentrics, between 1.1 and 1.5 kHz.
One of my favourites, the TAD Labs 2402 studio monitor, crosses over the 2-inch-exit compression driver (TD-4001) at 650 Hz with a 12 dB/oct. slope, and the 16" woofer (TL-1601a) at the same frequency, but with a very steep 36 dB/oct. slope.
Toole presented in his book, a sound power level measurement
of a loudspeaker placed in an anechoic room. They took 70
measurements (36 horizontally and 34 vertically) in 10 deg
increments (vert.=speaker on its side, horiz.= on its bottom).
Ideally it would be best to take measurements spaced equally
around the imaginary sphere, but this process turned out to be
a good approximation.
Sound Power Level(dB)=20*log((p1+p2+...pn)/n*po)
Find the sound pressure(pn) of each frequency SPL at different angles
with: SPL=20*log(pn/p0)
p0= reference sound presure =2*10^(-5) Pa is 0dB SPL
n= number of measurements
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Hi Charles, speaking only for BMS, (I sell them), the neo generally speaking is more powerful, and can focus more power in the gap, and will have a slightly higher flux density. Also, as explained to me by the factory, both magnets will have a curve, where the flux density varies according to power, but the neo has a knee, that if used correctly will have less flux variation throughout the power band. To me they sound more refined. In the same vein, the reason alnico magnets are so sought after is that they have lower variation in flux density, but are now too expensive, both in terms of money, and geo-political factors, to use.
Regards, Jack Arnott
Assistance Audio
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