Easiest software to measure the Frequency Response

[claudio]

Nando,
the generic calibration file works, while a real calibration file works very well. It's a matter of how precise your measurement needs.

 

[-_nando-_]

Interesting !

How much did you pay for the microphone and pre-amp ? Did it come with calibration file ?


Claudio, if the masurement accuracy have an error of +/- 10% is okay... Do you think that is possible to achieve it this way ?

 

[claudio]

Claudio, if the masurement accuracy have an error of +/- 10% is okay... Do you think that is possible to achieve it this way ?

It's better to talk in dB: +/- 1dB accurancy, in my opinion.

 

[-_nando-_]

It's better to talk in dB: +/- 1dB accurancy, in my opinion.

Wow !! GREAT !!!!!!!!!!

 

[bzdang]

Prices around USD 50. to 60. each

http://www.musiciansbuy.com/APEX_220_Measurement_Microphone_APEX220.html

http://www.musicworksgroup.com/cata...preamp-preamplifier-phantom-power-p-1064.html

These types of mic are flat enough in typical crossover frequency ranges to be useful even if uncorrected. Kudos to those who are advanced enough in crossover development that the mic calibration makes or breaks a design (that would not be me ).

 

[Salas]

Re: Store-bought mic and preamp + Camera Tripod

Hi all, I tried very hard to use speakerworkshop but came to the conclusion that I needed to set up a dedicated computer for measurement to avoid wrecking the audio setup. It has very good capabilities and thanks to helpful users it is well documented, but a bit challenging to set up.
I bought audiotester after trying the shareware and finding it very easy to get it working. Recommended.
I'm interested in Arta but haven't found time yet, fortunately winter weather arrived yesterday in the Great Lakes region and speakerbuilding season has begun.
Because of 3 kids and two jobs I have not enough time for everything audio-related, so I decided that to buy a mic and preamp in order to spend my limited hobby time on loudspeakers instead of building instrumentation (heh, haven't heard about diymicrophone regional meeting yet).
I purchased the inexpensive mic and preamp listed in links below,
and there may be similar products available from other manufacturers. fwiw, the mic is an ECM8000 clone, and it looks to have a panasonic mic element at the business-end.
Also, disclaimer, I work for the company which imports these devices (which just means that I got the employee discount).

APEX220 Measurement Microphone
http://apexelectronics.com/index.php?tmp=4&id=83

APA1 Mic Pre-amp w/ Phantom Power
http://apexelectronics.com/index.php?tmp=4&id=44

You will also need a mic cable of the kind with xlr ends (15ft) is useful length. And adapter from 1/4" phone plug to RCA jack to connect to sound card line in with a cable having 2x RCA to 1/8 stereo plug.

TIP - I tape the mic to the handle of a camera tripod so that I can adjust the height easily and point it at the loudspeaker. Most tripods have a crank for fine adjustment of height.

Hello

I also use a tripod, but I have made a suitable extention so to avoid taping the calibrated mics.

 

[Salas]

As for generic calibration files be very doubtful when applying them. My 2 mics have same Panasonic capsule but in one its burried in its edge for ruggedness (outdoors use) and in the other is protruding a little being sensitive if hit on the floor. Edge diffraction for the rugged mounting gives a monotonic last octave rise of +4dB vs +1dB for the sensitive one! Both are compared to B&K calibrated system and compensated with suitable calibration files offcourse. But just dont trust that a mic assembly keeps with the capsule characteristics. Beautiful thing when we have a reference though is that we can compensate ANY mic against reference. I have algebrically deducted my Radioshack's SPL meter response from my references and used the outcome as a calibration file. Its the most handy one now, bcs it has a built in preamp, shows SPL by its own and its rugged. Plus it mounts directly to that tripod.

 

[Patrick Bateman]

Re: Store-bought mic and preamp + Camera Tripod

Hi all, I tried very hard to use speakerworkshop but came to the conclusion that I needed to set up a dedicated computer for measurement to avoid wrecking the audio setup. It has very good capabilities and thanks to helpful users it is well documented, but a bit challenging to set up.
I bought audiotester after trying the shareware and finding it very easy to get it working. Recommended.
I'm interested in Arta but haven't found time yet, fortunately winter weather arrived yesterday in the Great Lakes region and speakerbuilding season has begun.
Because of 3 kids and two jobs I have not enough time for everything audio-related, so I decided that to buy a mic and preamp in order to spend my limited hobby time on loudspeakers instead of building instrumentation (heh, haven't heard about diymicrophone regional meeting yet).
I purchased the inexpensive mic and preamp listed in links below,
and there may be similar products available from other manufacturers. fwiw, the mic is an ECM8000 clone, and it looks to have a panasonic mic element at the business-end.
Also, disclaimer, I work for the company which imports these devices (which just means that I got the employee discount).

APEX220 Measurement Microphone
http://apexelectronics.com/index.php?tmp=4&id=83

APA1 Mic Pre-amp w/ Phantom Power
http://apexelectronics.com/index.php?tmp=4&id=44

You will also need a mic cable of the kind with xlr ends (15ft) is useful length. And adapter from 1/4" phone plug to RCA jack to connect to sound card line in with a cable having 2x RCA to 1/8 stereo plug.

TIP - I tape the mic to the handle of a camera tripod so that I can adjust the height easily and point it at the loudspeaker. Most tripods have a crank for fine adjustment of height.

I agree 110% about using a dedicate PC. It will save you a ton of time. Right now I have to adjust the volume levels every time I measure, which wastes about 15 minutes.

Right now I'm assembling a PIII 450mhz for Speaker Workshop, which I bought at Boeing Surplus. The whole computer was just $40 IIRC.

http://www.boeing.com/assocproducts/surplus/retail/

 

[Vikash]

Re: Re: Store-bought mic and preamp + Camera Tripod

Now, if we could just find an available, affordable, and reasonably good microphone

I have searched the forum, but the answers seem to indicate several 100 $$$ s worth of Behringer, almost as much as a good ready-made loudspeaker (god forbid!).

Svein B

http://www.madaboutsound.com/prod.asp?pname=MPK

I've worked with Speaker Workshop a lot, and it simply can't compare with ARTA. It's much simpler, consistent and a joy to use in comparisson.

I think we should order the Panasonic WM61A from Digikey, and build a pre amp with the most plain frequency response possible.

WM-61A datasheet:
http://www.panasonic.com/industrial/components/pdf/em06_wm61_a_b_dne.pdf

The Digikey part number is P9925-ND. Price is the incredible 1.86usd per unit.

Then just download the dataset from Claudio Negro's webpage, and you're done:

http://www.claudionegro.com/download/WM61A.zip

Run Speaker Workshop with the tips from Patrick (use 48Khz), and Claudio Negro's website have lots of tips too:

http://www.claudionegro.com/ or click in his www.

Now we should search for a good pre-amp schematic, almost easy to build and with plain response.


That's it !! I think the thing is easier than we imagined before...



Best Regards,


Fernando

Again, having been through all this, I decided to offer to the Wallin Preamp PCB (or kits), and the WM-61A capsules in the UK through Mad About Sound.

I agree 110% about using a dedicate PC. It will save you a ton of time. Right now I have to adjust the volume levels every time I measure, which wastes about 15 minutes.

With Speaker Workshop, Quickmix is the answer to reverting your volume levels in a second.

 

[mr_push_pull]

I've spent ages trying to figure out Speaker Workshop. I know that most people here are in love with SW, but I find it one of the most user unfriendly tools I've encountered It took me half an hour to get ARTA working, and it's what I'd use if needed to make speaker measurements again. Great tool, intuitive, provides minimum required and not more.

 

[claudio]

Guys,
just to remember you that Arta is a measurement tool, Speaker Workshop is a speaker oriented design and measurement tool.
They are both free, with some limitation on Arta, and in my agenda there is a measurements comparison test of the two programs, since I like Arta too.

 

[-_nando-_]

ARTA is really nice

But SW seems to be more accurate

 

[bzdang]

ARTA is really nice

But SW seems to be more accurate

And precise too!

Vikash, the mic kit looks terrific.
Do you plan to offer a Wallin Jig as well?

 

[Vikash]

ARTA is really nice

But SW seems to be more accurate

You should back such bold statements up!

Off course ARTA doesn't replace SW by any means, in fact I import all my ARTA measurements into SW. As Claudio says, ARTA is only the measurement part and not for complete speaker design. In fact ARTA's overlay functionality is a royal pain to use. However for actual measurements it is far better than any of the other measurement suites I've tried regardless of cost.

No plans to offer the jig, although I must say that it is an indispensable tool. If you think of building one then I would add a chip amp inside at the same time. It's the only thing I didn't think of doing and wish I had.

 

[bzdang]

.... I would add a chip amp inside at the same time. It's the only thing I didn't think of doing and wish I had.

My thoughts exactly, or perhaps a teeny-weeny classD amp from 41hz.

 

[ergo]

I went one step further and also added VU meters to the front panel of my measurement box.

I always hated to do "on site" measurements and when no result start the quesswork if it's the PC acting up or software or a bad connection. With the VU meters I have feedback of measurement box outputs - so makes the faultfinding much faster.

An externally hosted image should be here but it was not working when we last tested it.

 

[-_nando-_]

Cool equipment !

 

[Matt_Tillard]

Hey all,

I spent a little bit of money, and bought an M-Audio Transport for an electrical interface, and bought the personal version of WinMLS, 2000. I think the Transport was like $65 on eBay, and WinMLS was $80. Looking back, I should have spent another $20 on the software to get whatever next step they had. The M-Audio USB audio is wonderful. It is capable of 24bit 96kHz sampling, and has a very low noise floor, somewhere around -80db. I can post some measurements if you would like to see them. I'm going to be using Linkwitz's recommended microphone and preamp, you simply cannot get any better quality or reliability for the price!! All in all, I am very happy with the quallity for the price.

Matt

 

[Salas]

You did a very wise move.

 

[-_nando-_]

Hi !

I finishied my Speaker Workshop configuration !

I already calibrated the sound card, amplifier and microphone, but where should I "click" to start the measurement