'The Missing Link': 600-4kHz

[cuibono]

I'm trying to expand my OB system - I currently use a 8" driver from 200-2000Hz, but want to improve the system's off axis performance. The 8" driver starts to beam above 700Hz (being about -2dB at 60deg; by 1k, its error is -7dB). So I'm looking for a special driver to cover 600-4000k (which includes XO room). Here are my criterion, in order of importance (remember this is an OB system):

-smooth in band response

-capable of 105dB SPL rms, peak around 110dB (approx.), considering both power and mechanical limits (Sd=90cm, Xmax=2mm or more should do, I think)

-small enough diameter to avoid beaming (must be 5" or 6" nominally)

-must have acceptably low distortion at high levels (@100dBSPL/1m, tall order better than -55dB down)

-decent sensitivity (>88dB/2.83V/1m - 95dB would be nice, don't know if its possible?)

-decent cost ($50, $80max per driver?)


I've found a driver I consider acceptable: the SBacoustics SB15NRXC30-8 (see Zaph's data at http://zaphaudio.com/5.5test/compare.html
It covers all the bases well, only I wish it were more sensitive.

So is there any driver out there that can match this driver for smoothness, size, output and distortion, but better its sensitivity without breaking the bank?

I realize pro drivers are more sensitive, but rarely come less than 6", and are rarely less than $80. I've been playing with the Dayton PK-165 ($24), but its distortion is much too high below 1k.

Any ideas for 'the missing link'?

[prickears]

D'day,

Other than 87 db, how does vifa pl11mh-09-08 fit the bill?

Regards, Mick.

[BHTX]

Just curious..

What 8" are you using? And for highs? Active or passive?

If sensitivity is of any importance, have you considered the waveguide route? There still aren't nearly enough choices on the market though, which can make things tough, but it can be done with an 8" mid for sure. On the other hand, you'll need to either be very proficient in passive crossover design, or have an extremely flexible active solution.. with the ability to use different slopes at different frequencies and EQ, at the very least. So, rather than going for a smaller mid, why not work above your current one and improve things?

Just a thought.

[CLS]

Why do you set a goal of [60 deg off axis response] to a dipole speaker? Isn't that pretty much facing the 'side' of speaker? (60 deg off the front, that's 30 deg off the side) Near the side of a dipole speaker, front and back waves are cancelling each other, aren't they? So how is it possible to have a 'good enough' 60 deg off axis response?

[sangram]

Not sure about HD, but the Seas MCA15RCY seems to fit - 89.5dB, ruler-flat response to 5KHz, 5" diameter and ~$70. The Scan-Speak 12M will also fit, but at >3 times the price.

[otto88]

95 dB?

Fostex 166/ 167, with or without being EnABLed

http://www.planet10-hifi.com/fostex.html

Also goofle Bob Brines

[meister_gue]

What about these: http://www.beyma.de/fileadmin/seiten...al/6P200Nd.pdf

http://beyma.de/fileadmin/seiten/dow...z-6MI90_1_.pdf

[GM]

http://www.parts-express.com/pe/show...number=290-015

http://www.parts-express.com/pe/show...number=290-020

[mcfabo]

4" come mid near 90db\w\m?
off axis response is very good to 2k, dynamics is excellent. i think at 600hz the limit is more electric than mechanic

ciao,fabio

[cuibono]

Originally Posted by BHTX

Just curious..

What 8" are you using? And for highs? Active or passive?

If sensitivity is of any importance, have you considered the waveguide route? There still aren't nearly enough choices on the market though, which can make things tough, but it can be done with an 8" mid for sure. On the other hand, you'll need to either be very proficient in passive crossover design, or have an extremely flexible active solution.. with the ability to use different slopes at different frequencies and EQ, at the very least. So, rather than going for a smaller mid, why not work above your current one and improve things?

Just a thought.

Mid is currently Dayton RS225 (was Visaton B200), high is BG Neo3, XO at 1.5k, all active. I'm not sure I understand you - are you saying put a wave guide on the 8"? Yes, rather than add a small mid, I would love to use something that could cover 800Hz all the way up, but it must be dipole and less than 5" wide, for best off axis response. I'm not ready for compression drivers yet. A custom AMT might do it, but I don't want to do that yet either...

Originally Posted by CLS

Why do you set a goal of [60 deg off axis response] to a dipole speaker? Isn't that pretty much facing the 'side' of speaker? (60 deg off the front, that's 30 deg off the side) Near the side of a dipole speaker, front and back waves are cancelling each other, aren't they? So how is it possible to have a 'good enough' 60 deg off axis response?

My current design goal is smoothest off axis response possible, in dipole format. I've been working towards it recently, and, IME, off axis response is easily perceivable. Dipoles cancel most at about 90deg, but still not completely - they are often only about -25dB down. At 60deg, an 'ideal' dipole is supposed to be -6dB down, and I look at this angle because it most shows any deviation from an ideal off axis angle. I've been finding improvements to the off axis behavior to make instrument's "tonality" more natural.