Suprabaffle Options Sim Study. SDB (sidebaffle)
I own a pair of FE166E BIBs, and I wasn't much satisfied with the "plane jane" response of the slender BIB front. Just a matter of personal taste.
The usual answer that can be read here is either to add a BSC filter, or try with a suprabaffle. I resisted to believe a circular suprabaffle would provide much help to counter the BSC need. I did a simple test, and wasn't much satisfied either.
After this real world hearing tests I decided that the BIB deserved some more R&D, and did some simulations with Tolvan's "The Edge".
This are the results of the simulations, and the design of my alternative SDB.
First: standard BIB, FE166E build to the results of the BIB calculators that can be found at Godzilla's site, with GM's formulea.
Drawing
FR
Second: BIB with simulated circular-like suprabaffle. Rest of dimensions unchanged. Notice the "bump" in the mids, the rapid fall in the midbass, just where the BIB mouth output is falling down, and the dip in the high mids...
Drawing
FR
Third: BIB with an "optimum" SDB (side-baffle). Rest of dimensions unchanged.
Drawing
FR
Of course this is only one side of the reality. It doesn't show the integration of the mouth and the driver radiation, but to me was evident that the sound without an addition was lacking "something"
What I found is that this additional side-baffle not only looks well on paper, but it sounds well too. The FE166Es got the ability to "disappear" like the FE108ESigmas do !!!
I did the tests with just the leftovers of the build of the BIB, asymmetrically mounted . The right BIB SDB, was mounted to the left of the BIB, and the left BIB SDB, mounted to the right of the BIB.
I think it is a very easy test to do, with *no mods at all* needed just to see if you like how they sound, so totally worth a try.
The left BIB is on its own corner, and the right one is just wall supported.
I will definitely mount the SDB with hinges to improve the WAF, so as I can "transform" the BIBs for listening and make them slender looking for when they are not in use (or when I have guests
).
I hope this can add a new dimension to the BIB world, and give the sawdust-addicts a good excuse
Gastón
EDIT: Image links were coming and going.
I own a pair of FE166E BIBs, and I wasn't much satisfied with the "plane jane" response of the slender BIB front. Just a matter of personal taste.
The usual answer that can be read here is either to add a BSC filter, or try with a suprabaffle. I resisted to believe a circular suprabaffle would provide much help to counter the BSC need. I did a simple test, and wasn't much satisfied either.
After this real world hearing tests I decided that the BIB deserved some more R&D, and did some simulations with Tolvan's "The Edge".
This are the results of the simulations, and the design of my alternative SDB.
First: standard BIB, FE166E build to the results of the BIB calculators that can be found at Godzilla's site, with GM's formulea.
Drawing
An externally hosted image should be here but it was not working when we last tested it.
FR
An externally hosted image should be here but it was not working when we last tested it.
Second: BIB with simulated circular-like suprabaffle. Rest of dimensions unchanged. Notice the "bump" in the mids, the rapid fall in the midbass, just where the BIB mouth output is falling down, and the dip in the high mids...
Drawing
An externally hosted image should be here but it was not working when we last tested it.
FR
An externally hosted image should be here but it was not working when we last tested it.
Third: BIB with an "optimum" SDB (side-baffle). Rest of dimensions unchanged.
Drawing
An externally hosted image should be here but it was not working when we last tested it.
FR
An externally hosted image should be here but it was not working when we last tested it.
Of course this is only one side of the reality. It doesn't show the integration of the mouth and the driver radiation, but to me was evident that the sound without an addition was lacking "something"
What I found is that this additional side-baffle not only looks well on paper, but it sounds well too. The FE166Es got the ability to "disappear" like the FE108ESigmas do !!!
I did the tests with just the leftovers of the build of the BIB, asymmetrically mounted . The right BIB SDB, was mounted to the left of the BIB, and the left BIB SDB, mounted to the right of the BIB.
I think it is a very easy test to do, with *no mods at all* needed just to see if you like how they sound, so totally worth a try.
The left BIB is on its own corner, and the right one is just wall supported.
I will definitely mount the SDB with hinges to improve the WAF, so as I can "transform" the BIBs for listening and make them slender looking for when they are not in use (or when I have guests
).I hope this can add a new dimension to the BIB world, and give the sawdust-addicts a good excuse
Gastón
EDIT: Image links were coming and going.
Wow Gastón... maybe you are onto something - leaving BIBs in their corners and adding a piano hinged 'wing' that conveniently folds out for listening and back when not in use. If your measurements reflect upgraded performance (smoother and more extended bass) and listening tests are encouraging, your wing could become an 'add on' option for critical listening. I will try it and see how it sounds. The only problem i can see in my crowded listening room is having enough room to unfold the wing. But i do think it's a neat idea and can't wait to try it out. Thanks for putting the thought into this and reporting your results!
Godzilla
Godzilla
Godzilla said:
This might be an interesting effect. I suppose if the wig is just
an outrigger that it might be made of some lightweight material.
The technique I have for making grilles is to use the assembly for making screen doors but with fabric instead of mesh. I'm wondering how the extension can be effectively executed as part of the
design.
Still wondering about the double baffle. The driver could be brought down to simply all this but I haven't heard anything from our resident Simms.
zBuff said:
Yes, they do... they are only sims, and of course results are depending on each different setup. I would say that for the straight BIB and the simulated "dish" suprabaffle, they feel like right for what I heard.
zBuff said:
The reasons of the shape were: wing width = width of the leftover I had (now it has been promoted from leftover to BIB Wing. One SW fan could name them "Wing Commanders"
).Height and angles: This I sized to minimize nasty peaks.
What I intended with this is just to show an alternative approach that could work (adding a full body baffle, and that symmetrical things appeal to the mind but not necessarily are good in the FR domain. Also that perhaps the "dish" should be correctly sized with other than an aesthetics approach.
An interesting thing I got from the sims were that symmetrical wings of any shape always added a peak in the response. With the right sizing that could be used to iron some particularly annoying dip.
A couple more sims (one of them is only a check I did on the symmetry / size of a suprabaffle, and the other one has a flatter response, less LF support, and needs a supportive Significant One
)Drawing
An externally hosted image should be here but it was not working when we last tested it.
FR
An externally hosted image should be here but it was not working when we last tested it.
Drawing
An externally hosted image should be here but it was not working when we last tested it.
FR
An externally hosted image should be here but it was not working when we last tested it.
BTW, creative designs as proposed by johninCR that are part of the FrugelHorn docs now could also be useful... I would take the "> and <" shaped ones but not the ArtDeco coffin ones
Godzilla:
I'm glad to be able to add something to the BIB Body of Knowledge... I hope it works for you and the rest.
Gastón
Gastón I am already making plans to add wings! Your sims are too good to ignore. Unless they sound terrible, i plan to hinge wings that simply fold back undetectable. The way my BIBs are built this will be totally reversable if not satisfied.
http://www.zillaspeak.com/bib-godzillabib.asp
I was in my garage tonight looking thru piles of scrap wood to use and found several pieces. I want to do something decorative as well as increase the sonic performance of my BIBs. If the wings change the sound it will be worth experimenting with. I think it will make changes to the sound. Once some experimenting is done and some positive experience is had would it be ok to add your contribution to the BIB site? I would like to use your drawings and sims (crediting you for your idea of course). I wonder if your idea might eliminate the ripple some seem to complain about and smooth out the BIB response. Ripple or not, BIBs still sound excellent. Imagine if they also measured excellent too. Moving this design forward is a great idea for DIYers that want great back horn sound and efficiency without the difficult woodworking required for so many back horns. Yours is an easy retrofit. I do hope it's an improvement sonically.
Godzilla
http://www.zillaspeak.com/bib-godzillabib.asp
I was in my garage tonight looking thru piles of scrap wood to use and found several pieces. I want to do something decorative as well as increase the sonic performance of my BIBs. If the wings change the sound it will be worth experimenting with. I think it will make changes to the sound. Once some experimenting is done and some positive experience is had would it be ok to add your contribution to the BIB site? I would like to use your drawings and sims (crediting you for your idea of course). I wonder if your idea might eliminate the ripple some seem to complain about and smooth out the BIB response. Ripple or not, BIBs still sound excellent. Imagine if they also measured excellent too. Moving this design forward is a great idea for DIYers that want great back horn sound and efficiency without the difficult woodworking required for so many back horns. Yours is an easy retrofit. I do hope it's an improvement sonically.
Godzilla
loninappleton said:
Not sure I completely follow especially WRT to the double baffle Vs 'extra piece', whatever it is.
If by 'extra depth' you're referring to the driver being mounted on a double thickness baffle, then as long as this 'tunnel' is expanding at least at a 90 deg included angle (which can be 'stepped', i.e. internal hole diameter is larger by at least 1.5" if 0.75" thick), it should actually be closer to the sim since this extra volume should ~offset the loss in the tight confines of the pipe horn due to the driver's bulk.
GM
GM said:
The only extra piece would be the double baffle. I cut extra pieces in case I don't hit the mark for a hole cut out or some other snafu occurs.
This particle board is under 3/4 depth. Doubling up will not be as deep as normal particle board or ply. It's maybe 5/8 for shelving.
If I do this, I will measure off of one, center the pilot hole and do one piece with 4 in hole saw and one with a 5 in.
I've done this and chamfered for the Harvey. Also tried it in combination with a jimmy-rigged supra baffle on the GM MLTL.
I do not know if my plan to have a flush mount jig will happen all of a piece with this particular build. If I have to free hand another one, hey, at least I'm getting practice.
Non parallel side walls?
Has anyone tried making a BiB with non parallel side walls? I was thinking of trapezoidal shape if view from the top, flare out to the back, looking from the front.
I figure it would change the expansion rate assuming you didn't reposition the internal baffle. It take away one of the best things about the BiB, the ease of build, especially the internal baffle would be alot harder to measure and cut. But are there any advantages to be gained?
Also can anyone think of a way to magnet mount a driver in a BiB?
Has anyone tried making a BiB with non parallel side walls? I was thinking of trapezoidal shape if view from the top, flare out to the back, looking from the front.
I figure it would change the expansion rate assuming you didn't reposition the internal baffle. It take away one of the best things about the BiB, the ease of build, especially the internal baffle would be alot harder to measure and cut. But are there any advantages to be gained?
Also can anyone think of a way to magnet mount a driver in a BiB?
Godzilla said:
That's great !
I hope you like the results.
If you want to do a coarse test, this would be the results (front baffle contribution only) with just a wood strip sitting to a side of the BIB. A wide front baffle with a non-symmetrical location for the driver.
Drawing
An externally hosted image should be here but it was not working when we last tested it.
FR
An externally hosted image should be here but it was not working when we last tested it.
Notice the additional ripple between 500Hz (highest peak) and 2KHz. Almost 2dB. Not annoying IMO, but in this case, bigger is not necessarily better. It will let you feel the change in the midbass without need of drilling or cutting, at the expense of changes in the most sensitive area of our hearing.
I wouldn't implement this full baffle when a better approach is visually more appealing too, but that's just me.
The front baffle of my BIB, that was as a whole calculated with the calculators to be found in your site (http://www.zillaspeak.com/bib-howtobuild.asp) are:
*external* height: 178cm = 70.08"
*external* width: 26cm = 10.24"
The full wing (no shaping) is 23cm = 9.06" width.
The "optimized" wing in this case starts at
y=30cm=11.81"
and end at y=166cm=65.35" on the BIB side.
The farthest (shortest) side of the wing starts at y=40cm=15.75"
and ends at y=150cm=59.06".
Feel free to publish all of this information. I think that a mention to "The Edge" would be a nice touch, as it is what I used for the analysis. But first let's let your ears decide if it's worth
Gastón
So I'm considering making a pair of BiB's, using some canadian speakers ( McBride's from http://www.loudspeakers.ca/ ), but I'm concerned that they don't list the full T/S parameters, or even have a SPL-vs-frequency graph available (I already asked)...
So is this enough info to build a BiB? Will I be able to measure the T/S parameters directly?
CAVALIER 8
8” foam edge
McBride
dual cone fullrange
Outside Dia...........................208 mm
Impedance...............................8 ohm
Power ........................................30 W
Freq. Resp ................40 Hz - 18 KHz
Magnet Wt ................................10 oz
Fs .............................................40 Hz
Voice Coil Dia .........................25 mm
SPL...........................................92 db
Depth ......................................82 mm
Baffle Opening......................183 mm
Mtg. Cntr...................195 mm BC x 8
Cheers,
Mitch
So is this enough info to build a BiB? Will I be able to measure the T/S parameters directly?
CAVALIER 8
8” foam edge
McBride
dual cone fullrange
Outside Dia...........................208 mm
Impedance...............................8 ohm
Power ........................................30 W
Freq. Resp ................40 Hz - 18 KHz
Magnet Wt ................................10 oz
Fs .............................................40 Hz
Voice Coil Dia .........................25 mm
SPL...........................................92 db
Depth ......................................82 mm
Baffle Opening......................183 mm
Mtg. Cntr...................195 mm BC x 8
Cheers,
Mitch
I tried adding a few different sized wings today. There is a definite change in the sound. I hear added weight to vocals (i spent about 30 minutes listening to a Squeeze CD with and without wings). Vocals are fuller, especially on multi singer harmonies. I liked the change but have to decide what size wings to make. My BIB uses the 165k driver so it is in the 165, 166, 167 family of Fostex drivers. To me, the best sounding wing was about 6 inches wide by about 60 inches tall as compared to a wing 11 inches wide by 30 inches tall. I may split the difference and make some cosmetic alterations ending up with a wing 7 inches by 42 inches and call it a day. This way i can enjoy the improved sonics as well as enjoy this unique wing feature. I may play around with more sizes but am convinced for now this will only make the BIB even better. I have no measurement tools, just my ears. But i did like what i heard. If you think vocals sound thin on your BIBs this is a tweak to play around with.
Very cool,
Godzilla
Very cool,
Godzilla
Yeah, but they are doing it without adding anything inline with the signal/source . This has to do with wave propagation off the baffle, and is IMO a MUCH better alternative to a BSC circuit , being closer to a cure rather than a quick fix.
Wide baffles rule.
....................................Blake
Wide baffles rule.
....................................Blake