Dayton Audio DATS & Omnimic

Dear All,


if I want to test my father's old bass and midrange drivers (and maybe redesign his 3-wawy boxes) am I better with DATS or Omnimic ?

I'm thinking about if there are any overlappings between the 2 tools. According to my understanding, DATS is more of a speaker driver test and measurement tool (measuring real T/S Parameters too - I'll need it, these drivers have no datasheet at all) ... while Omnimic is rather a room measurement system for whole ready setups, producing some useful stats and showing us weak points which can (or need to be) compensated via DSP.

The question is:

1) is DATS alone capable of measuring frequency curve ? (SPL) OR do I need Omnimic (and a good silent echo-less room) for that ?

2) is Omnimic alone able to measure T/S Parameters of a bass driver while being capable of doing a lot of other stuff too ?
 
Hi Vortex,
if you have a multimeter, a sine wave generator a 10ohm 1/2 watt resistor and an amplifier, you can measure T/S parameters manually. It takes more time but cheaper than DATS.

Measuring Loudspeaker Driver Parameters
If you are serious about loudspeaker measurement, you will need one such as emm6 that is used with a sound card as to get a timing reference.
USB microphone may have the phase information normalized by the software.
 
Hi Vortex,

I use DATS V3 to determine speaker parameters and OmniMic to obtain frequency responses (FR), and more.
For FRs OmniMic uses short sine sweeps which have to be played from typically the track #2 on their test CD (a .wav file which you can store anywhere).

I'm thinking about if there are any overlappings between the 2 tools.

Not sure if there is some overlap, however there COULD be a very useful synergy between both products:
The DATS software is capable of generating three forms of sine sweeps but NONE of them works with the OmniMic FR measurement system. IMHO this is a missed chance, because a DATS sweep generator directly driving a speaker while OmniMic recording the FR would be very handy.
Today you need an extra amp setup to play the test track.

Perhaps Dayton Audio is listening...

Andre
 
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Hi Vortex,
if you have a multimeter, a sine wave generator a 10ohm 1/2 watt resistor and an amplifier, you can measure T/S parameters manually. It takes more time but cheaper than DATS.

The amp has to have a very low output impedance.

Manual measurement actually directly measures the numbers needed to calculate T/S. DATs measures the impedance curve and then guesses the T/S.

You can get more useful data from something like S+L WooferTester 2.

Do note that these inexpensive tools do not collapse the T/S curves at the same place as the typical factory software and i have found not as useful for designing boxes. Very useful for driver matching thou.

dave
 
The DATS software is capable of generating three forms of sine sweeps but NONE of them works with the OmniMic FR measurement system. IMHO this is a missed chance, because a DATS sweep generator directly driving a speaker while OmniMic recording the FR would be very handy.
Today you need an extra amp setup to play the test track.

Oh, nothing extra seems to be needed. DATS is driven by the sound card so anything you play on the PC will be output onto the DATS leads. So you can play OmniMic track #2 (or other) on the PC and use DATS as amp to drive the speaker, while measuring the actual speaker response using OmniMic mike + software. Works well.

This feature is hard to find in the Dayton Audio documentation (if even present). Extra selling point.

Andre
 
The amp has to have a very low output impedance.

Manual measurement actually directly measures the numbers needed to calculate T/S. DATs measures the impedance curve and then guesses the T/S.

You can get more useful data from something like S+L WooferTester 2.

Do note that these inexpensive tools do not collapse the T/S curves at the same place as the typical factory software and i have found not as useful for designing boxes. Very useful for driver matching thou.

dave

So you say WooferTester2 is a better option for T/S parameters than DATS ?
 
I think - or hope - to get results after some break-in closer to reality than factory parameters. Almost all drivers deviate somehow from factory stated T/S parameters, at least there're only a very few who really keep factory values. Depending on brand and type the deviation can be small or even a bit larger, but at least I'm closer to reality before tuning the box.
 

PRR

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2003-06-12 7:04 pm
Maine USA
www.diyaudio.com
I think - or hope - to get results after some break-in closer to reality than factory parameters. Almost all drivers deviate somehow from factory stated T/S parameters....

Mass, area, and magnetic strength won't change.... where would they go?

Suspension stiffness *does* change with break-in. Fs and Q will change about as square-root of change of stiffness.

But in most box speakers, system stiffness is more about the box than the suspension. So the system parameters change very little despite change of test T/S parameters.

The most extreme deviation would be an open-back guitar speaker. One popular recipe is to pick Fs near 90Hz and T/S Q near 1, then use with an under-damped amplifier so system Q is near 2. Put this in a box sized for dipole loss below 160Hz. The box is down 6dB at 80Hz, the underdamped speaker rises 6dB at 80Hz, and the response is fairly flat to the low note of guitar. Here the suspension stiffness is not swamped by any box stiffness. However the really stiff suspensions do not break-in as much as the super-limp spiders in for-box speakers. And the "error" mostly means one note is a dB louder than another, which the player can compensate in plucking.