Planar Speaker Asylum

Welcome! Need support, you got it. Or share your ideas and experiences.

Return to Planar Speaker Asylum

Planar Speaker Asylum

RE: What is the purpose of the rear wave in dipole speakers? Can you just put planars in a box?

96.234.41.97

hahax@verizon.net

In Reply to: RE: What is the purpose of the rear wave in dipole speakers? Can you just put planars in a box? posted by jodaboda@gmail.com on August 19, 2015 at 14:54:19

There are trade offs with having a back wave. It causes interference problems with the front wave which causes bass to roll off faster. And it means you need to position such speakers carefully so the back wave reflection doesn't cause many problems. But being tall there is less vertical dispersion and therefore less floor and ceiling reflections to deal with. And the front to back interference also means there is less side radiation causing reflection problems from side walls.

And yes you can close the back on a planar but I've only seen it done for tweeters sometimes when combined with regular dynamic drivers and one time that I recall for a mid-range planar.

Follow Ups:

if I went for an enclosure, I'd attempt a wedge shape - Mart 07:52:45 08/20/15 (0)
Minis don't have bass frequencies with ( their geometrically increased need for size & structural energy ) which to contend.

However, planars in general sound ( at least to my ears ) more sensitive to enclosures than traditional magneto-dynamic dome & cone drivers.

So, I'd use lessons learned from less "boxy" sounding conventional speakers. I'd see if the midrange could be housed in something resembling a sealed version of a Bowers & Wilkins N805... keeping the true-ribbon tweeter separate lest the midrange hastens the tweeter's demise by mistreating the it as a passive-radiator.

... just my 2� ♪ moderate Mart ♫
☺ Planar Asylum
where speakers are thin & music isn't
RE: What is the purpose of the rear wave in dipole speakers? Can you just put planars in a box? - Satie 22:16:49 08/19/15 (0)
Obviously the rear wave is there to make trouble...

You can seal the back of the planar in a box and some do so. But then you get box colorations you can only get rid of with heroic bracing and damping. Think VMPS RM30 or RM40. They needed restuffing and additional bracing to get the most our of them. The enclosure also forms an air spring so reduces the speed of the diaphragm slightly. On the other hand it adds to dynamics (see Jenzen box electrostatics) and efficiency so you can use a smaller panel to cover a large bandwidth.

The problem is that you trade off the reverberant field the backwave creates once it is delayed sufficiently.It helps define spaces better.

The normal solution to having space constraints is to use extensive diffusion and place the speaker 2-3 feet out. If you need to have them closer up then you need absorption as you suggest. But it needs to be broadband absorption so is likely to be layered. You might like the presentation that way as it retains the inherent speed of the drivers, and it can enhance clarity. But that will be at a loss of the ambient feel and have a dry sound that some can't tolerate - a bit like an anechoic chamber. There is a reason nobody wants to listen in one of those "perfect acoustics".You can overcome this to an extent with a really bad SET constantly driven hard so it produces lots of 2nd order harmonic distortion that can trick the ear into an illusion of a regained reverberation and alleviate the dryness.
RE: What is the purpose of the rear wave in dipole speakers? Can you just put planars in a box? - Roger Gustavsson 22:09:15 08/19/15 (0)
For frequencies above circa 150 Hz you can have planars drivers in a box. The cavity need to be carefully damped though. The best exemple I know of were made by SAC in Germany using Fostex planar drivers, http://www.sac.de/sac/start_frame.php?Pfad=140_143&BL=3

Quad ESL-57 is using damping behind their drivers, bass will still pass but higher frequencies will not.

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors: