Erin's Audio Corner (my new site/YouTube page)

Bohlender Graebener Neo10 Planar Transducer is up.

Klif's notes: Very non-linear frequency response. Odd things in the unit-to-unit consistency with regards to the distortion. I know people have used them and liked them... I don't see it.* Maybe there's a legit use for them that I'm just not aware of like line arrays (as the marketing indicates). Either way, I can't recommend them for 'standard' speaker applications based on what I'm seeing here.

https://www.erinsaudiocorner.com/driveunits/bg_neo10/


​​​​​​​https://erinsaudiocorner.com/images/...0/IMG_5354.jpg

Scanspeak 10F/8414G10 Discovery 4 inch Fullrange

Cliff's: Really good fullrange driver. Nice on/off-axis response linearity with the apparent breakup pushed out to ~16khz. A mild rise in output on the top end (to help combat the otherwise falling response off-axis) that could be easily flattened via DSP with a shelf filter if one were so inclined. Great usability above 300-500hz for higher output (to help overcome the mid-80's sensitivity). Truly an impressive driver for only $73/each (as of this writing).

If needing to use this as a midrange, though, I'd still recommend the actual 4-ohm midrange version of this driver if for no other reason than to gain back the sensitivity this one loses thanks to its fullrange purpose.

https://www.erinsaudiocorner.com/dri...g10_fullrange/






Attachment 9300

AudioFrog GB40 Midrange Review

Cliffs: Very low distortion. Nice usable range from 200/300hz to 3khz (low end depending on output; 200hz shouldn't be an issue for most, though but 300hz is easily doable for really high output-minded folks).

Link here:
https://www.erinsaudiocorner.com/dri...udiofrog_gb40/

https://erinsaudiocorner.com/images/...0/IMG_2235.jpg

Good news! I got a quote from Klippel this morning. As expected, however, it’s not cheap. Regardless, I’m moving forward and will be sending payment shortly. But I would really appreciate any donations from the community that I can get to help me offset those costs and, namely, to help fund some of the other things I would like to purchase to help me make my testing more efficient and accurate.
If you don’t mind helping out, you can use the link below to contribute to via PayPal (they take 3%, I’m OK with that):

https://www.erinsaudiocorner.com/contribute/





If you don’t care about the rest of the details then there’s no need to read any further. However, if you’re interested in what your donations would be going toward, keep on reading…


I want to provide as much accurate information as I can about drive units, speakers and whatever miscellaneous ‘tasks’ I take on. IMHO, Klippel products will provide far more depth of knowledge than anything else and that’s why I’ve chosen their product(s). But I also want to keep my hobby/family balance. Testing takes up a good deal of time; but it's not so much the "test" as it is the setup/takedown time: cutting baffles, setting up the measurement rigs, getting the cabling out and running all the wires, fixing the driver/speaker to the test stand, and then writing up the report. In the time it takes to get prepped for a test I can complete another test cycle.

To help with accuracy and efficiency, I also hope to build a dedicated "test" space in my attic. I have about 11x17 feet that I'll need to floor, wall, and insulate to make it a test room. The reasons this is important to me are:
1) Scientifically speaking, the space would be large enough to push the first reflection out another 1 or 2 milliseconds which may not sound like much but is another 200hz or so of accuracy in my measurements. 200hz is a lot when you're expanding that over multiple octaves.
2) It gives me a fully repeatable environment to work within whereas my garage is a state of constant flux with temperature, humidity and ... stuff. Having a dedicated area means that the ambient conditions are within reason throughout the year but also it means that I won't have to spend hours setting up gear and taking it down to complete a couple tests which would help me complete more tests over time.
3) If I were to go this route I could also build an ‘infinite’ baffle to help with drive-unit testing.

Another thing that would help immensely is a small, tabletop, CNC. For raw driver testing I use a large baffle which has a cut-out for inserting smaller baffles. These smaller baffles are the pieces that the raw drivers are attached to. In my previous years of testing I didn't have the ability to surface mount complex drivers or oversized flange drivers. This was a detriment to my results (I always noted when that was the case). Surface mounting is the proper way to test drivers. I do own a router but the time it takes to cut flush-mount surfaces for some drivers … well, it adds up over time. Therefore, I would also like to purchase a small, table-top CNC router so I can cut my baffles to the exact dimensions needed for a driver cut-out. I've got my eye on an item that is just large enough to cut the baffle templates I need.

The third thing is having an automated turntable for polar measurements (on/off-axis frequency response). Now, I can build one from wood … I’ve done it before. But it’s a manual turning system which consists of: measure speaker, go turn speaker, measure speaker, go turn speaker… doing that in 5 to 10 degree increments over 90 to 180 degrees takes time. So, it would be really nice to use one that’s automated and works with the Klippel where I could click the run button and let it measure and rotate automatically. Again, this helps with repeatability and accuracy. But these are not cheap, either. I’ve gotten a couple quotes back > $3k. So, this is probably more of a pipedream at this point.


Obviously I wouldn’t be doing this if I didn’t enjoy it and feel like I’m learning from it as well so I’m not about to cry “woe, is me” here. But presenting data to the masses requires an extra level of accuracy and robustness that throwing together a simple test setup in my spare bedroom and caveating to the nth degree cannot provide; I know this from experience. So anything you can donate to help me with that would really and truly be appreciated.

Thanks again,
- Erin

Quote:

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Originally Posted by erinh

Good news! I got a quote from them this morning. As expected, however, it’s not cheap. Regardless, I’m moving forward and will be sending payment shortly. But I would really appreciate any donations from the community that I can get to help me offset those costs and, namely, to help fund some of the other things I would like to purchase to help me make my testing more efficient and accurate.

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Can you point to a post or explain who them (and what) is?

Whoops! Fixed. Copy/paste error.

Klippel. :)

Quote:

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Originally Posted by erinh

Whoops! Fixed. Copy/paste error.

Klippel. :)

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I was hoping you were going to say that. :) Are you getting the laser measuring module too? I know that is expensive as HE-double hockey sticks. You definitely need to get some donations and should based on everything you’ve done for the community.

Sure did. This is a list of everything I got:

1 DA2 - Distortion Analyzer 2
Item No.: 2000-002 processor unit for all modules (incl. cable set) Refurbished unit Revision 2.1

2 LPM - Linear Parameter Measurement
Item No.: 1000-400 identification of linear electrical and mechanical parameters

3 LSI Woofer + Box - Large Signal Identification Woofer + Box for DA2
Item No.: 1000-230 identification of linear, nonlinear and thermal parameters of woofer drivers in free air, sealed and vented enclosures

4 LSI Tweeter - Large Signal Identification Tweeter for DA2
Item No.: 1000-220 identification of linear, nonlinear and thermal parameters of tweeters, micro speakers, compression drivers in free air

5 TRF Pro - Transfer Function Measurement Professional
Item No.: 1000-910 measurement of transfer function, harmonic distortion and rub & buzz

6 DIS Pro - 3D Distortion Measurement Professional
Item No.: 1000-810 DIS features + measurement of HI2 and amplitude intermodulation distortion

7 TBM - Tone Burst Measurement
Item No.: 1001-109 peak SPL measurements using tone burst signals (CEA2010)

8 PWT Pro - Power Test Professional
Item No.: 1000-700 power testing with temperature measurement and transducer identification

9 Pro Driver Stand
Item No.: 2211-002 transducer fixture with laser and microphone positioning (incl. laser calibration spacer), Rev. 1.5

10 Laser Set ANR 1282
Item No.: 2102-010 +/- 20mm, for woofer + midrange (incl. Controller ANR 5132)

11 Mic 17 IEPE 1/4"
Item No.: 2400-103

12 Cable; BNC - BNC, 2m
Item No.: 2300-106 Microphone cable, BNC male to BNC male, 2m, low capacitance coaxial cable type, blue

13 Mic Holder; MK10, for 1/2" Mics, fixed
Item No.: 2400-206 fixed Mic Holder for 1/2" mics, made of plastic, 1/4" mounting thread

14 Manufacturer Calibration DA, PA, PM8
Item No.: 6000-001 DA, PM8 or PA calibration with formal certificate, recommended every 2 years

The one thing I'm excited to have is the Pro Test Stand. It has connection points for the mic and laser and will fit various size drive units.
Edit: This is used for getting T/S parameters and namely linear xmax. Not for Frequency Response related measurements. A baffle will be used for FR measurements of drive-units like I've always done.

https://www.klippel.de/fileadmin/_pr...825206b59e.png

Wow Erin, that is an investment!
I hope you get the value out of that rig man.
The test stand is really nice too!