• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

Wormhole 9 Octaves Wideband

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I comissioned a really nice wideband driver made by SEAS.
It has something in common with their standart version but my design is more linear, has less distortion and looks better.
The unique parameters allow a low frequency extention down to 32Hz.
The price to pay is a rather big cabinet with 88 liters of volume.
Over xmass i had now time to listen.
I am very satisfied with the result.
I decided to offer a kit and this thread is about it.
I will publish more info and pictures soon.
 
3 cu ft? as big as some subwoofers. But... wideband makes it interesting.

I can see using this in a particular shape cabinet that would yield some benefits in terms of flatness of mid band response that would make the added volume not terribly difficult to live with.

What sort of sensitivity, impedance and diameter is this driver?

_-_-
 
The cabinet is rather wide and high but not very deep. That helps with the baffle step. The driver is placed off center for a smoother response. The driver has an 8" basket, 8 Ohm and i dream about 95dB sensitivity. Maybe 93dB sensitivity is more realistic. I have to make a calibrated measurement.
Most of the impedance is over 8 Ohm because the driver has really low mechanical loos so the peaks in the bass from the reflex are of high magnitude. Also there is EQ, mainly to drop the response in the upper midrange. Because this EQ is done in series with the driver the impedance goes uop in that area.
 
My wideband has this one as basis :
http://www.seas.no/images/stories/prestige/pdfdatasheet/H1597-08_FA22RCZ_Datasheet.pdf
It has two major ploblems :
You see an impedance mismatch between 500Hz and 800Hz.
This is the (in)famous edge resonance where sound from the voicecoil reaches the edge and travels back, partly canceling and partly amplifying the amplitude response over a certain range. This is a typical problem in a driver that has a low damping sorround.
It goes away with a high damping surround but that swallows deatil and micro dynamics.
What also happens is distortion, mostly second that is not so bad ( a sign of chaos ) but i would like to see that reduces because it can reach up to 3%. That does not sound crossly distorted but it swallows and masks some information.
My driver has a hand applied edge coating that improves that situation but keeps the low loss surround.
My driver also differs over 8kHz where it is diffuse field equalized to compensate for the unavoidable beaming in wideband drivers. So there is some more energy on axis to compensate a loss off axis. I think Ted Jordan is doing the same and also the Manger ( more or less ).
The magnet system of my driver has a rubber jacket that makes it more pretty and damps resonances somewhat.
 
frugal-phile™
Joined 2001
Paid Member
FA22RCZ...

These are quite a good driver, especially once tarted up.

FA22-calinda-enclosure.jpg


My driver has a hand applied edge coating that improves that situation but keeps the low loss surround.

Mine too.

dave
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.