I want to put Fostex Fe 206e drivers into a good cabinet. I am 90% converted to BIB, half wavelength, However after two weeks of searching, with many frutrated attempts to reach the BIB Calculator, all I have are a few contardictory dimensions.
I need a simple ENGINEERING solution, i.e.
1) Dimentioned drawing, or the few critical dimensions
2) Any details of stuffing required, if any
3) Any details of method to effect the v joint between the baffle and front panel
4) Where are the connecting wires brought out - through the baffle ??
I'm fine with woodwork and would be happy to tackle acoustic theory, but really just want to get on and listen to my music,
Cheers Bob Wade
I need a simple ENGINEERING solution, i.e.
1) Dimentioned drawing, or the few critical dimensions
2) Any details of stuffing required, if any
3) Any details of method to effect the v joint between the baffle and front panel
4) Where are the connecting wires brought out - through the baffle ??
I'm fine with woodwork and would be happy to tackle acoustic theory, but really just want to get on and listen to my music,
Cheers Bob Wade
Robert,
1. Not sure if Zilla's site is up yet, but you can download the BiB calculator from the following link, post #39:
http://www.diyaudio.com/forums/full-range/190224-enclosures-hemptone-fr8-4.html
Also attaching a pic showing the basic BiB layout - this was either in one of the BiB calculators and/or at Godzilla's site.
2. Attaching a pic showing the basic stuffing scheme.
3. The "slant" is attached to the two side panels and is flush with the front baffle. I would suggest:
a) Cut the slant pieces an inch longer than required
b) when building, start with a side panel first - lay it on a flat surface and do all the necessary markings for the slant on the inside of side panel. Then glue on the slant.
c) Glue on the bottom and back panel too.
d) After the glue has dried, glue on the other side panel- assume you have clamps and/or some weights to put pressure - this is a BIG panel.
e) Since the slant is longer than necessary, some part of it will be sticking out of the top. Once both sides are glued on, you can saw off extra bit
f) Line adjacent areas behind driver with 1/2" thick felt, put in necessary stuffing
g) Attach front panel. I prefer keeping a part of the front panel removable for adjusting stuffing
4. Connecting wires - I like to drop them to the bottom and take them out through the rear. Some folks prefer making a small hole in the slant to get the wires to the back - the hole can be filled up with glue/epoxy. Both are fine.
For BiBs to work optimally they need to placed near corners - would you be able to do that?
1. Not sure if Zilla's site is up yet, but you can download the BiB calculator from the following link, post #39:
http://www.diyaudio.com/forums/full-range/190224-enclosures-hemptone-fr8-4.html
Also attaching a pic showing the basic BiB layout - this was either in one of the BiB calculators and/or at Godzilla's site.
2. Attaching a pic showing the basic stuffing scheme.
3. The "slant" is attached to the two side panels and is flush with the front baffle. I would suggest:
a) Cut the slant pieces an inch longer than required
b) when building, start with a side panel first - lay it on a flat surface and do all the necessary markings for the slant on the inside of side panel. Then glue on the slant.
c) Glue on the bottom and back panel too.
d) After the glue has dried, glue on the other side panel- assume you have clamps and/or some weights to put pressure - this is a BIG panel.
e) Since the slant is longer than necessary, some part of it will be sticking out of the top. Once both sides are glued on, you can saw off extra bit
f) Line adjacent areas behind driver with 1/2" thick felt, put in necessary stuffing
g) Attach front panel. I prefer keeping a part of the front panel removable for adjusting stuffing
4. Connecting wires - I like to drop them to the bottom and take them out through the rear. Some folks prefer making a small hole in the slant to get the wires to the back - the hole can be filled up with glue/epoxy. Both are fine.
For BiBs to work optimally they need to placed near corners - would you be able to do that?
Attachments
Last edited:
Thanks for replies, just what I have been looking for. I'm surprised everything seems to be in inches - wonder why this is ? When the French agreed to the Greenwich meridian it was a trade off against Britain going metric at a "convenient time" - which didnt come till the 70's !
Thanks again - now to buy some sheets !
Cheers Bob Wade
Thanks again - now to buy some sheets !
Cheers Bob Wade
Phase Changes in TW/Horn Speakers
In trying to decide what enclosure to put Fostex FE206 drivers into I have been forced to do some thinking. My maths is not up to Fourier analusis, but a few sine waves on graph paper help !
Whatever ones choice in music it cannot be denied that the biggest challenge a Hi (FIDELITY) system can face is faithful reproduction of full orchestral colour.
And this colour is produced by harmonics - thinking of instruments like the oboe, bassoon, clarinet and so on. In fact we are, at bottom. trying to deal with an infiniely variable piece of physics.
However, if one considers one important example - the third harmonic, or the "fifth" in music. This is importantly present in. for example an open string, a reedless organ pipe etc.
So lets us "play" a 32' (c35Hz @ 25 C) organ pipe through our back loaded speaker, assuming that the tuned length is half wavelength of this frequency. The "back" sound wave must, by definition, be in antiphase to the front wave. This wavefront will emerge from the port, assuming an acurate line length, in antiphase, therefore subtractive to the front wave. Thus the COLOUR of this organ note will be changed. Similar changes are obviously going to occur through the effective low frequency spectrum of the enclosure.
So my question is, with these enhanced low frequency designs are we really only talking about strong base, such as might impress the guy in the next car at the traffic lights; and this at the expense of true fidelity ??
I would welcome any comments that shoot this down as I am presently in a conumdrum ! However I must say that I do find many of the subjective comments one finds unhelpful, to say the least.
A further question I have is what is the preceived advantage of the symetric "horn" types such as the Kirishima which Fostex seem to recommend ?
regards Bob Wade
In trying to decide what enclosure to put Fostex FE206 drivers into I have been forced to do some thinking. My maths is not up to Fourier analusis, but a few sine waves on graph paper help !
Whatever ones choice in music it cannot be denied that the biggest challenge a Hi (FIDELITY) system can face is faithful reproduction of full orchestral colour.
And this colour is produced by harmonics - thinking of instruments like the oboe, bassoon, clarinet and so on. In fact we are, at bottom. trying to deal with an infiniely variable piece of physics.
However, if one considers one important example - the third harmonic, or the "fifth" in music. This is importantly present in. for example an open string, a reedless organ pipe etc.
So lets us "play" a 32' (c35Hz @ 25 C) organ pipe through our back loaded speaker, assuming that the tuned length is half wavelength of this frequency. The "back" sound wave must, by definition, be in antiphase to the front wave. This wavefront will emerge from the port, assuming an acurate line length, in antiphase, therefore subtractive to the front wave. Thus the COLOUR of this organ note will be changed. Similar changes are obviously going to occur through the effective low frequency spectrum of the enclosure.
So my question is, with these enhanced low frequency designs are we really only talking about strong base, such as might impress the guy in the next car at the traffic lights; and this at the expense of true fidelity ??
I would welcome any comments that shoot this down as I am presently in a conumdrum ! However I must say that I do find many of the subjective comments one finds unhelpful, to say the least.
A further question I have is what is the preceived advantage of the symetric "horn" types such as the Kirishima which Fostex seem to recommend ?
regards Bob Wade
Hello Bob
I'm trying to decide whether to build a BIB or Voigt pipe for Fostex FE206En drivers.
I have reservations about the phasing between input signal and back wave since these, I believe have the potential to alter the harmonic content (hench fidelity/ colour) of what will be heard. e.g I have an Electronic World article here from an engineer who built some active speakers (once a pet project of mine) which from c30Hz to 100 Hz show pahse angles of up to 100 degrees, which I believe are not acceptable.
Regards Bob Wade
I'm trying to decide whether to build a BIB or Voigt pipe for Fostex FE206En drivers.
I have reservations about the phasing between input signal and back wave since these, I believe have the potential to alter the harmonic content (hench fidelity/ colour) of what will be heard. e.g I have an Electronic World article here from an engineer who built some active speakers (once a pet project of mine) which from c30Hz to 100 Hz show pahse angles of up to 100 degrees, which I believe are not acceptable.
Regards Bob Wade
Distortion - The Truth Sought
Now being into THIRD thoughts about what type of enclosure to build I now issue a plea/challenge.
Is anyone prepared to say, in the simplest terms, which type of enclosure will produce the least distortion, perhaps exclusive of inermodulation distortion ?
Remember someone marketing audio under the label "Original Sound" - so lets hear what the Instrument (musical) would sound like if played in THE room.
Regards Bob Wade
Now being into THIRD thoughts about what type of enclosure to build I now issue a plea/challenge.
Is anyone prepared to say, in the simplest terms, which type of enclosure will produce the least distortion, perhaps exclusive of inermodulation distortion ?
Remember someone marketing audio under the label "Original Sound" - so lets hear what the Instrument (musical) would sound like if played in THE room.
Regards Bob Wade
One possible solution to "lowest possible distortion":
A high-quality compression driver feeding a conical (or any) horn, driven well within its performance limits. The rationale is that the (extremely light and sturdy) diaphragm moves only a miniscule amount, while the conical horn profile is said to produce less distortion than other horn profiles (but has its own drawbacks, thus it's easy to argue for other profiles).
A multi-way horn also has the advantage of being easy to dial in (with regard to the acoustic centers of each unit, i.e., time alignment). On the downside, it can get very expensive and can take years (although Autotech in Poland has numerous amazing horns you can buy now).
Bang for the buck, a widebander is hard to beat for simplicity. Listen to the widebander in a vented box for a few years while you build the horns
A high-quality compression driver feeding a conical (or any) horn, driven well within its performance limits. The rationale is that the (extremely light and sturdy) diaphragm moves only a miniscule amount, while the conical horn profile is said to produce less distortion than other horn profiles (but has its own drawbacks, thus it's easy to argue for other profiles).
A multi-way horn also has the advantage of being easy to dial in (with regard to the acoustic centers of each unit, i.e., time alignment). On the downside, it can get very expensive and can take years (although Autotech in Poland has numerous amazing horns you can buy now).
Bang for the buck, a widebander is hard to beat for simplicity. Listen to the widebander in a vented box for a few years while you build the horns
Hi chris661,
I wish I understood more. But they are quite the paradox. Despite the huge-ness, and the SPL capability, in my experience, it seems the owners play those systems more quietly than I'd imagine. They just barely "breathe" at you, they are so quiet and gentle.
And they can do razor-sharp 3D imaging. I don't know why. I agree there must be a lot of diffraction (e.g., when the tweeter is barely able to get out from behind the other units).
I wish I understood more. But they are quite the paradox. Despite the huge-ness, and the SPL capability, in my experience, it seems the owners play those systems more quietly than I'd imagine. They just barely "breathe" at you, they are so quiet and gentle.
And they can do razor-sharp 3D imaging. I don't know why. I agree there must be a lot of diffraction (e.g., when the tweeter is barely able to get out from behind the other units).
Enclosure Distortion
Well I seem to have struck THE taboo subject ! The deafening silence re my question on minimum distortion surely speaks volumes !
Surely this can only mean one of two things - either no one has reliably compared the distrotion penalties associated with various designs OR - some poeple know but are nor prepared, for whatever reason, to make the information widely available.
Bob Wade
Well I seem to have struck THE taboo subject ! The deafening silence re my question on minimum distortion surely speaks volumes !
Surely this can only mean one of two things - either no one has reliably compared the distrotion penalties associated with various designs OR - some poeple know but are nor prepared, for whatever reason, to make the information widely available.
Bob Wade
I can't imagine anyone here is sitting on an answer and not telling you. Are you implying that some of the contributors have a vested interest in not sharing this?
Do you have any thoughts on the subject? It might be easier to start a discussion by sharing some thoughts rather than issuing a challenge for you to judge the results of.
Kyle
Do you have any thoughts on the subject? It might be easier to start a discussion by sharing some thoughts rather than issuing a challenge for you to judge the results of.
Kyle
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.