affordable diagnostics and the like

[Dax617]

I have a triamped system with external crossovers. Is it possible to use this diagnostic tool by patching into the speaker wire going to the individual driver while still mounted in the speaker. Possibly a question for the manufacturer, but because I have a rack mounted system complete with computer it is tempting. Anyone had experience with this or something better.Here is the link http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=390-802&ctab=6#Tabs

[sfogg]

Measuring electrically isn't what you need, you need to measure

acoustically. A radio shack SPL meter into your computers soundcard

will get you in the ballpark with something like:

http://homepage.ntlworld.com/john.mulcahy/roomeq/index.html

Shawn

[3dzapper]

The equalized disc, calibrated for the Radio Shack SPL meter, from Rives Audio might come in handy.

Rick

[edwinr]

Measuring acoustically is definitely the way to go. Then you can fine tune by ear...

[sfogg]

Rick,

No need. I believe the measurement software can apply the inverse of

'C' weighting to the measurements. That is all the 'corrections' tfor

the RS meters do... correct for C weighting that the meter applies.

There are mods out there to make the RS meters measure flat response

too for those that want to go that route.

Shawn

[Dax617]

I have to admit I love 2005 for hardware and applications to give a reasonable base line to the novice with a wieghted interest to evaluate and tweak the the rule of past masters and superstiton of the newly ignorant. Bravo, I will check it out. thanks again

[Dax617]

Shawn ,my aim in this exercise would be to judge the health of the driver. I have to admit a blown tweeter was not particular apparent on my tweeter(k horn). Supposen I were to say the drivers are perfect electronically( including crossover etc) I could adjust accoustically for the descrepancy. Using the method subscribed I could adjust the room response. Can I use this input from a fluke meter, is it just an input adapter from the meter to the computer (software)? In other words the first step is to see whether or not I have proper input and performance from the speakers (baseline) and then hopefully identify and treat acoustically with in the rooms parameters (never perfect, I am not an audiophile per say more of an engineer) .

[sfogg]

No, electrically measuring the driver tells you nothing you need for

this. If you tried to setup the system so that electrically the FR

looks balanced you will acoustically have a system that is unbalanced.

Why? Because physically the efficiency of each driver in converting

electricity to sound differs.... each driver has a different

efficiency. Feed the same voltage level signals and each driver is

going to be playing back acoustically at different SPLs.

You need to measure the *sound* the driver is producing. That means measuring acoustically with a mic in the room.

Go buy a $35 Radio Shack SPL meter and get the cables you need to plug

it into the soundcard in your computer. Then use the software I

referenced above.

Shawn

[Dax617]

Roger, I read this. @ what point does bass become omni directional in your opinion ( 100 Hz)?

[WMcD]

Dax,

The answer is "no". The box and software is not going to do even a fraction of what you are seeking to do.

I have not used that box. However, the description shows that it will do a good analysis of the electical input impedance of a speaker or system. This is the classic means of measuring T-S parameters of a driver.

To do that in any testing system you really need to test the woofer alone, and then alter either the mass (by adding known mass) or adding spring (by adding a rear box of known size).

I.e. the mechanical and electical qualities of the woofer can't be infered from an impedance test alone. You must alter a mechanical parameter. Then a lot of info on the driver can be infered from the change in input impedance..

Then, per T-S analysis and projection, there is a theoretical output when the accuraely measured driver is in a theoretically perfect, or known imperfect, box.

But actuall acoustic output might not be perfectly predicted. Then we're not even talking about room effects.

So, I think you're on the right path. But it is very difficult. All along the way there must be measurement, design, cross checking, re-measurment, good modeling of what is going on, what can be solved, and how.

The leader is the LMS-LEAP program and analysis. Very expensive.

Gil

.

[Dax617]

thanks for the response Gil. the consensus seems to be an empirical understanding of your environment. Now the age old question nature vs nurture. how do I determine,are the speakers in working order and my quest is environmental instead of bad cross over or driver performance? How do I determine that an anamoly is not a bad crossover point or driver failure but is an accoustical mode etc. I observe these things @ the theoretical sweet spot .Surely I am not looking for a definite answer as it impossible to seperate the witnesss from the incident ( as in ufo sightings) just your opinions. May be the question is how do I verify all drivers are in working order and the cross over points are correct.