BG Neo10 Testing

[ErinH]

A guy here sent me 4 of these to play with so I baseline tested all 4, compared them against each other, then did the full testing on the better of the 4 samples.

The one thing I will say is that 3 of the 4 perform really bad in terms of HD. The one I wound up doing further testing on looked much better but still wasn't great.

The FR on these rises +10dB from 1khz to 3khz and winds up at +18dB from 1khz to about 8khz. Off-axis response on the horizontal axis looks pretty good with some issues above 5khz. CSD shows ringing around 6khz which shows up in every FR measurement as well. Vertical off-axis response is bad but I've yet to see a ribbon/planar that isn't bad vertically. (bad meaning no controlled dispersion... just wonky).

HD isn't too bad; some spots here and there may be of concern but nothing terrible and overall 3rd is pretty low (minus the peaky spots). *Now, if you look at the comparison HD plots, it's an entirely different ballgame and the HD is so high/sporadic that it's just scary.*

Crossed from 300-2khz seems to be where I'd be expecting to land - if I were using them in my own setup - given the upward swing in response and the poor vertical dispersion off-axis.


Link:
http://medleysmusings.com/bohlender-...ar-transducer/


teasers...

[OlderMongrel]

Nice to see these tests, very good site! It's interesting how such meticulous tests as you are doing often yield different results from manufacturer's specs. To paraphrase the old saying, "A man with test data on his drivers knows how they should sound, but one with two sets of data is never sure."

John

[peterlrabbit]

Your data may very well suggest a high degree of variability in quality control but on the flip side, it also might provide solid evidence that these drivers are not as robust as some might hope and need to be used carefully to avoid damage. The extremely low compliance of some planar and ribbon drivers makes "full range" use a dicey proposition. I was a bit skeptical at first when these drivers were recommended for low midrange usage and that feeling hasn't changed. If these drivers were overdriven at all before you received them, that would likely explain the huge disparity in distortion you're seeing. The resonance curves suggest that the "cleanest" measuring driver had the "tighest" suspension. A comparison of compliance associated inductance between the samples might provide another indication that the "suspensions" of the three poor performers were either significantly out of spec due to manufacturing defect or hard use. Did the person who supplied them to you indicate if and how they were used?

[jeff_free69]

I didn't see it mentioned, but I assume the test baffle is pretty standard - big & essentially "infinite".

Some people seem to like using these B&G drivers as a dipole (high up on my daydream to-do list .
I'm just wondering how that might affect the FR.

[ErinH]

Your data may very well suggest a high degree of variability in quality control but on the flip side, it also might provide solid evidence that these drivers are not as robust as some might hope and need to be used carefully to avoid damage. The extremely low compliance of some planar and ribbon drivers makes "full range" use a dicey proposition. I was a bit skeptical at first when these drivers were recommended for low midrange usage and that feeling hasn't changed. If these drivers were overdriven at all before you received them, that would likely explain the huge disparity in distortion you're seeing. The resonance curves suggest that the "cleanest" measuring driver had the "tighest" suspension. A comparison of compliance associated inductance between the samples might provide another indication that the "suspensions" of the three poor performers were either significantly out of spec due to manufacturing defect or hard use. Did the person who supplied them to you indicate if and how they were used?

Bolded... I agree entirely. I could imagine something falling in to the membrane would easily cause issues and may very well be the culprit of my results. That's the reason I chose Sample 3 to test with as it performed the best of all the samples.

Edit: He didn't state the condition. He did state that one sounded off to him. I kind of wonder if that one that sounded off was the better of the 4. Things that make you go hmmm...

Regardless, the data is cool to see and it does make a point about taking care of these, if this is indeed the case. I do recall seeing someone else mention seeing these HD issues in their data, too. If you look at Zaph's results, the spikes in HD are there but not at the same level I measured with my samples.

[ErinH]

I didn't see it mentioned, but I assume the test baffle is pretty standard - big & essentially "infinite".

Some people seem to like using these B&G drivers as a dipole (high up on my daydream to-do list .
I'm just wondering how that might affect the FR.

I test all drivers dipole in a large-ish baffle.

http://medleysmusings.com/test-setup-and-methods/

[greywarden]

Wow, they are pretty much useless lower than 200Hz and above 800Hz where the off-axis response is varying wildly...

[r-carpenter]

Interesting.
I've tested 4 Neo3-PDR and they show less of a stellar performance then the units Zaph tested. Few DB deep at 8k and slightly higher HD (all tho it's hard to say exactly without controlled test).

[Face]

Wow, they are pretty much useless lower than 200Hz and above 800Hz where the off-axis response is varying wildly...

Unless it's a square ribbon, vertical will always drop off early. IMO, its still very usable from 300 to just over 2K. Pairing it to an elliptical waveguide loaded dome or similar shaped ribbon(such as RAAL), would make a good directivity match. Dan's latest speakers are an excellent example of how these should be used.

[greywarden]

Yes, but the vertical and horizontal FR graphs show the driver's off-axis response varying exactly at 800Hz

[framus]

I've used perhaps 100 of of the non-pdr Neo 8's in my Philharmonic speakers (crossed steeply at 600 Hz and 2900 Hz, dipole operation), and have never had any field failures. They're easy to work with in that range from a frequency response standpoint and have excellent distortion measurements. When the Neo 10 became available, I tested out a pair hoping I could cross them lower. They didn't measure as well as the 8's. I wrote to the tech guys at B&G and had a few exchanges, but I decided to stick with the 8's. I'm not sure I would run them full range, but they do make an excellent dedicated midrange, particularly in an open-back application. Dennis Murphy

[Face]

Yes, but the vertical and horizontal FR graphs show the driver's off-axis response varying exactly at 800Hz

So will any other 5" woofer: http://www.seas.no/index.php?option=...d=64&Itemid=88

[cvjoint]

Harmonic distortion wise they test similar to the Seas Excel Nextel 7" and the JBL 7" above 300hz @96db. Subjectively, to me they sound better than any 7" cone for pure midrange use.

[LFM2]

I have a question. Were the wires soldered directly to the terminals of the Neo10's. The reason I ask is that I built a pair of GRresearch Alpha line sources which use the non PDR neo 8. There are 8 per side. In the first 2 years I had these I had 2 Neo 8's fail. This would cause 4 in the line to stop working. I became worried that the remaining drivers had been damaged by soldering. I ended up replacing all 16 Neo 8's and connected these with spade lugs. The before and after change in performance was major. I spoke with Chris Brunhaver at B&G and he supplied the new drivers at a very good price. I suggested that the instructions shipped with the driver include a warning to use extreme caution when soldering. I don't believe that this happened. I am very pleased with the performance of the new drivers and have not had one fail in five years. I have 16 questionable Neo 10's in a box in my basement that I wouldn't sell to my worst enemy.

[cvjoint]

The Neo8s are known to melt if soldered. The Neo10s posts are much beefier but I don't know for sure if they would survive soldering. I've always skipped that step with BG units and used standard disconnects. On the Neo8 the terminals have to be reinforced for that too as they bend easily and can break over time with a few installations. The neo10 has this strong epoxy like material over the terminals to improve rigidity and it works.

[remlab]

I have a question. Were the wires soldered directly to the terminals of the Neo10's. The reason I ask is that I built a pair of GRresearch Alpha line sources which use the non PDR neo 8. There are 8 per side. In the first 2 years I had these I had 2 Neo 8's fail. This would cause 4 in the line to stop working. I became worried that the remaining drivers had been damaged by soldering. I ended up replacing all 16 Neo 8's and connected these with spade lugs. The before and after change in performance was major. I spoke with Chris Brunhaver at B&G and he supplied the new drivers at a very good price. I suggested that the instructions shipped with the driver include a warning to use extreme caution when soldering. I don't believe that this happened. I am very pleased with the performance of the new drivers and have not had one fail in five years. I have 16 questionable Neo 10's in a box in my basement that I wouldn't sell to my worst enemy.

I think you mean 16 Neo 8's in a box in the basement, not 16 Neo 10's

[remlab]

I've used perhaps 100 of of the non-pdr Neo 8's in my Philharmonic speakers (crossed steeply at 600 Hz and 2900 Hz, dipole operation), and have never had any field failures. They're easy to work with in that range from a frequency response standpoint and have excellent distortion measurements. When the Neo 10 became available, I tested out a pair hoping I could cross them lower. They didn't measure as well as the 8's. I wrote to the tech guys at B&G and had a few exchanges, but I decided to stick with the 8's. I'm not sure I would run them full range, but they do make an excellent dedicated midrange, particularly in an open-back application. Dennis Murphy

Dennis
Do you purchase all your Neo's directly from BG?

[Ron_E]

Dan's latest speakers are an excellent example of how these should be used.

Which speaker? Is there a link?

Ron

[S7910]

Which speaker? Is there a link?

Ron

The Echelon (the one on the catalog cover).