using a compression driver reverse mounted

[petervv]

hi guys,

I've got a wild idea, please comment.

I'm using Oris103 fronthorns with FE103Sigma drivers at the moment, as you know, the 103 is a 4" fullrange driver. This driver gives usable response from 200-9000Hz in the fronthorn and sounds quite nice.

I've got a pair of big Fostex D582 2" compression drivers, these drivers use a 4" diaphragm.

I've been thinking about removing the rear cover of the 582 and bolt that side to the fronthorn using a suitable adapter ring, maybe remove the phaseplug.

I realise the suspension of the diaphragm is quite fragile, using it at 200Hz could be a challenge for the suspension, not usable for PA, but possible at 'home' levels??

looking forward to read your replies, Peter

[Hornlover]

It would no longer be a compression driver. I would think it would be better used as intended. Find or make an adapter for the Oris to go down to a 2" throat if you really want to use the compression driver.

[Cal Weldon]

Really, the things are designed and made to run through the phase plug. You can try but don't kill yourself if it isn't quite what you hoped. Either way, let us know, it sounds interesting

[ralphs99]

Hi Peter,

I've heard this idea before. Unfortunately it doesn't work very well.

The main problem is the very small Xmax of compression drivers; typically 0.5mm before the diaphragm hits the phase plug.
This limits the usable LF and the relatively large diaphram limits usable HF. So you end up with a driver only suitable for use between maybe 800Hz-2kHz.

Cheers,
Ralph

[ScottG]

despite all the naysayers thus far - it could actually work quite well depending on the driver.

several on the Hi Eff. board of the audio asylum have done this and in general have been quite pleased with the results (..driver and application dependent however). The x-max is always an issue but, typically eff. is quite high plus it sounds like you are contemplating horn loading, both of which will allow for greater spl's for a given x-max.

I say - give it a go and report back!

[petervv]

hi all,

thanks for the replies, as expected, opinions vary.

I did a few experiments already:
- I removed the rear cover of the 582 (and the horn), connected a sine wave generator through a poweramplifier and played a bit with freq and level. Response is quite strong down to approximately 100Hz.
- I measured (with my finger!) the movement of the FE103 in the horn while playing music at 'high' listening level, the cone barely moves.

I'm using a active (DCX2496) crossover, a steep highpass is no problem.

I'll keep you informed on the progress, could take some time because time is limited.

regards, Peter

[Magnetar]

You will get VERY limited response in a horn, very ragged response on top out of a horn and very low power handling either way at 500 cycles or below even if it's a beefy large format 4" diaphgram 2" driver.