Thoughts on the F120A or FE108ES2? - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th September 2005, 08:34 PM   #11
robertG is offline robertG  Canada
diyAudio Member
 
Join Date: May 2005
Location: Montreal
Default Still working on calculation!

Well, I don't know if the horn-bandpass hybrid will see light, from calculations, a pair of (BIG!) Onken enclosures with 15 inchers is the perfect match on paper:
similar efficiency (around 94dB)
very flat response from 40Hz (30Hz at -6dB)

Probably a good candidate for a 1st order Xover at around 100hz, which should relieve the FE108EZ of most of the excursion requirements...

Will see. I'll get the 15 in. driver next week and start on the Onken cab...
  Reply With Quote
Old 10th September 2005, 02:42 AM   #12
Jaime is offline Jaime  Uruguay
diyAudio Member
 
Jaime's Avatar
 
Join Date: Apr 2004
Location: Montevideo
robertG

I understand the difficulties of the little FE108EZ.
It has sensitivity 90 dB and Xmax = 0.28mm
But the FE168EZ has 94,5 dB sensitivity and Xmax = 1.6mm.
It works comfortable????.

When I said subwoofer I was thinking about a low bass driver.
The mid bass box probably is a good idea. But I believe that it must obligatorily be horn box.!!!!

An old article of Jean Hiraga in L'Audiphile magazine shows an idea that I like. But it would be necessary to calculate correctly.
http://www.geocities.com/dbr_audio/Subwoofer-Hiraga.pdf (fig 5)

best regards Jaime
__________________
I write in English worse than Tarzan
  Reply With Quote
Old 10th September 2005, 02:59 AM   #13
diyAudio Member
 
Join Date: Feb 2004
Location: los alamos
I have a pair of FE108ESII, and am REALLY impressed with them, compared to the FE206s, FE166s Fe167s I have.
Still breaking in, using open baffels until I finish a pair of swans...
Robert
  Reply With Quote
Old 10th September 2005, 03:30 AM   #14
robertG is offline robertG  Canada
diyAudio Member
 
Join Date: May 2005
Location: Montreal
Jaime,

The problem I found with the 168 is the beaming at upper-mid and high frequencies, and most of the sensitivity difference (compared to the 108) is there.

The peak at 7kHz is especially difficult to live with, and the only way to tame it is (apart from ear plugs) is to use a notch filter that will also reduce efficiency, so the difference in overall eff. is not that much.

True, the X max of the 168 is greater, but on the other hand, there is distortion (especially modulation of higher freq.) the minute there is cone movement. Since this excursion is there only for bass output and since bass output is (slightly) insufficient anyway, I guess the only sensible solution is to use one or the other as a low-to-high driver and using a dedicated bass driver(s) for really low frequencies (30 to 80hz).

I agree totally with the fact that a horn bass module would be perfect (provided sensitivities are matched). But to keep things simple and acceptable, I also think that a really large pro driver with something like 96dB eff. at 30 or 40 Hz, 15 in. driver might be "fast" enough to respect the impact ability of the sigma drivers.

I'm a big fan of Jean Hiraga and I read (and re-read) everything he wrote for La Nouvelle Revue du Son back in the 70s. What he refers to in his article is essentialy bandpass enclosures, which are OK to reproduce bass, but might not have enough BW to cover from let's say 25Hz to 80 or 100Hz (almost two octaves).

Problem with the horn-bandpass enclosure I calculated was a peaking sensitivity of around 110 dB/w/m at around 150Hz, thus needing a big (or active) filter to chop everything over 94dB from 40Hz or so to 100Hz, with brickwalls below and above the frequencies.

A very large reflex or Onken cabinet could be quite easy to optimize for around 94dB eff. from 30 or 40Hz all the way to 100Hz (just a simple low-pass in the circuit).

Ah, choices, choices, decisions, decisions!
  Reply With Quote
Old 10th September 2005, 07:40 PM   #15
diyAudio Member
 
Join Date: Jan 2005
Location: Ohio
Nice that others are chiming in. I think at this point, I'm going to stick with the 168 for now. I have to admit, I don't find any problem with beaming in my system. So not a huge concern for me. For some reason, I'm not hearing back from Eifl Japan, so that puts the stop to that driver, for the time being anyway.

I am going with a bass driver of some sort, similar to JC, though yet to be decided. I've thought of open baffle or a 12" pro sound driver ina box. I would prefer a 15", but the amount of room it takes becomes an issue. Also, too much bass would be an issue in my apartment.

Also, once I get things put together, I may try a tweeter of sorts for the upper end. Considering a ribbon or possibly even a Jordan JX53, if it would work. I have some T90as on a shelf, so I will proabably try those first, though not sure how they would perform as more than a super tweeter. (may roll the driver off a bit early to smooth out the treble, more of an idea right now than reality)

I'm considering the Bass Zilla plans as a starting point. Just something to work with.

Anyway, while the build isn't going to happen yet due to an exteremely busy schedule, I thought I'd update on my thoughts.
  Reply With Quote
Old 10th September 2005, 10:38 PM   #16
diyAudio Member
 
Join Date: Feb 2004
Location: los alamos
Quote:
Originally posted by robertG

I'm a big fan of Jean Hiraga and I read (and re-read) everything he wrote for La Nouvelle Revue du Son back in the 70s. What he refers to in his article is essentialy bandpass enclosures, which are OK to reproduce bass, but might not have enough BW to cover from let's say 25Hz to 80 or 100Hz (almost two octaves).
Any links?

Roert
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
f120a in DBR is done and :-/ better alternative? jaencer Full Range 4 13th April 2009 05:58 AM
WTB - Fostex F120A (PR) jkelly Swap Meet 0 30th October 2008 07:31 PM
Fonken for F120A drivers? jrebman Full Range 9 2nd January 2008 06:34 AM
F120A question juanito Full Range 1 12th August 2007 06:42 PM
Fostex F120A commstech Full Range 10 27th October 2004 05:39 PM


New To Site? Need Help?

All times are GMT. The time now is 10:27 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2