Best midrange with THD and waterfalls?

[Daveis]

Is anyone doing waterfall and THD measurements similar to Zaph? I'm looking for the ultimate 800hz to 4khz driver. Ideally, 2nd harmonics down 50db from fundamental. 3rd harmonic lower than 2nd across the board. All other higher harmonics buried under 70db.

Also, has anyone measured a lower THD tweeter than the Scanspeak AirCirc 6600. (I have a Seas Millenium and that measures only OK).

[Davey]

You might take a look on Mark K's website. He has test results for quite a few drivers....even some midranges. His testing methodology is somewhat different than Zaph, but more illustrative....IMHO.

http://www.markk.claub.net/Testing/testing.htm

Davey.

[Paul Ebert]

I'm looking for the ultimate 800hz to 4khz driver. Ideally, 2nd harmonics down 50db from fundamental. 3rd harmonic lower than 2nd across the board. All other higher harmonics buried under 70db.

Um... Doesn't the Dayton RS52 almost fit that bill?

Of course, if you want something more 'prestigious' the ATC SM75-150 is often touted as the ultimate mid. I haven't seen any distortion measurements for it, though.

I believe Mark tested the Accuton, which might be another contender.

[Daveis]

Thanks for your comments. I am trying to digest Mark's site.

I think I like the swept sine measurements better. I can see more data all at once.

Mark seems to recommend the RS52 in one grouping of mid's. I like the price and the performance I'm seeing.

In the other Midrange Group he tests data-Seas W15, M15, MCA15, Focal 5W, GR Research M130, and the Dayton RS150. But he's measuring only upto 850 hz. So I can't directly compare the MCA15 which he recommends to the RS52.

On Zaph's site, I see the SS 18W8531G beats the RS52 by a little bit. Which is weird since it's a larger driver.

[joecarrow]

Here's a key quote from Zaph's page where he tests the Scan Speak 18W8531G:

"And finally, note - Do Not compare these harmonic distortion plots to others anywhere else, including on this site. The test method was different for this particular set. Make comparisons within this test group only. If you want to compare results with the 5.5" grouping, the 6.5" group will need approximately 4dB added to the harmonics. It's shown a little lower."

So- you really can't compare the two drivers since the testing method is different. The main question is- how loud do you need the drivers to play? If you don't need extreme SPL, the RS52 could be an extremely nice mid.

If you really need it loud, the scan speak might be the ticket. On the other hand, you could buy three Peerless Exclusive 830-883 woofers for the price of one scan speak, or half a dozen RS180s.

Do you have some more details of your project? There is no "best driver", only "best for the application".

[Daveis]

Well, specifically, I'm trying to find a replacement for my BG RD40 planar which I am using between 800hz and 4000hz. Maximum playing volume is 85db at listening position. Average listening is at 75-80db at listening position. So I don't need extreme SPL's.

I plan on using the driver in a sealed box, not semi Open baffle like I'm currently using the RD40.

I plan to replace my Seas Millenium with a Scanspeak Aircirc 6600 above 4000hz based on Zaph's measurements.

I'm just starting to get into swept sine measurement myself. As inexpensive as the RS52 is I should just get a couple and try them. But if I find something that measures better in terms of 3rd and higher THD (800-4000hz) I'll get it.

Also, the Neo8PDR might be something else to try.

[JonMarsh]

The Neo8 will work well in that range, and measures quite well as far as distortion. The more important (and challenging) point might be integration of radiation patterns in the crossover region...

At 4 kHz the ideal maximum center to center distance is ~3-1/2".

[Daveis]

Jon, can the Neo8 be turned on it's side to get the mid and tweeter closer?

Is it better to have the tweeter to the side of the Neo8 rather than on top?

[ThomasW]

Jon, can the Neo8 be turned on it's side to get the mid and tweeter closer?

Not a good idea, that will limit the horizontal dispersion.