Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks?

[BudP]

leeoh,

You could EnABL the Jordan drivers. I am not sure if the Fostex drivers you have are EnABL'd or not. But, patterning the Jordan's makes them smooth and extremely sweet and detailed.

Bud

[leeoh]

Thanks for the advice Bud. No, they are not enabled. Not sure of the procedure anyway tho' I have often read posts from others who have done it. Seems like a lot of very careful calculations have to be made to get the spacing right. Comparing the 4 inch Jordans with the much larger Fostex isn't really being fair to the Jordans but the whole range of sound from bass to high frequency in the G Changs is so much better IMO. Maybe the experts would say that the high end of the Fostex lacks something, but if it does I am not aware of it. I wouldn't go to the expense or the trouble of adding a tweeter, even if I knew how to do it.

[BudP]

Seems like a lot of very careful calculations have to be made to get the spacing right.

True, but that has already been done and is free for the looking. Attached is a txt file with the known EnABL threads. The result of treating both Fostex and Jordan would be a narrowing of their sonic differences, aimed at more music with less incorrect sound. They would still have their same basic character, but be providing considerably more downward dynamic range (a Planet 10 comment I agree with).

Bud

[leeoh]

Thanks for that Bud. It has led me to some posts by Loni Appleton, which I am reading thro'.

[crappyjones123]

a few questions...forgive me if they have been answered already.

1. are there any other hardware components besides the following required for the construction of a fully functional bib? drivers, binding posts, wire to connect binding posts to driver, dampening material. the wood portion is going to be supplied by the gentleman building the speakers so i am just concerned with everything else. did i miss anything?

2. the drivers will be enabled fostex 206e's. i am a midrange junkie and like a decent amount of bass as well. i dont like piercing highs or hot treble at all. id rather have a nicer midrange and have some rolled off highs than have any peakyness on the top end. very sensitive to that. keeping this in mind, how should i instruct the gentleman building the speaker to stuff the cabinets?

3. as far as tuning the speaker goes, ive tried to find what exactly that means online but ive failed. so here goes the noob question anyways. i know it required some test tones to be played. but thats about it. what exactly is the process and how would i go about going through it if i were to do it myself? id also like to know if i have to give the gentleman who is going to be building these things the instructions. he is an electrical engineer and his partner his a woodworker. both play the bass guitar professionally and build the bass guitars as well. so any technical jargon that is likely to go over my head will probably be understood by them.

4. there is a 80% chance the speakers will be placed on carpet. would a plinth be advisable or would spikes just be enough? if a plinth/platform is a good choice, how tall would i have it be? is there a certain design to be used? plinth + spikes perhaps? ive heard metronomes on some carpet with 0 bass and then on wooden floors with nice clean bass. trying to avoid the first case with this question.

5. in a lot of commercial designs ive seen a small chamber at the bottom of the speakers to be filled with lead shot or sand which in turn helps in the bass response dept. instead of a plinth would a small chamber under the bib itself help at all or would it screw things up?

6. would it make a difference if the binding posts were mounted on the side of the cabinet (besides looking odd of course)? the wire from the driver to the binding post could be shortened without causing any interference to the sound.

7. any building tips i should pass along to the gentlemen building these speakers? any tips for after the speakers are built?

thanks,

cj.

[BudP]

CJ

Having read your comment on preferred sound character, please read this thread.
Measurements of Phase Plugged and EnABLed FE167E

And then email Dave Dlugos at Planet 10.
http://www.planet10-hifi.com/

I am not advocating you change your plans or your builders. Dave will be able to comment on the Fostex drivers from deep experience and he has been providing EnABL'd drivers on a commercial basis for two years now. Obtaining the Fostex driver of your choice, from Dave, will provide you with exactly what you say you want.

Bud

[crappyjones123]

bud,

the drivers i will be using are enabled. and they are being ordered from dave do i get a cookie for reading your mind?

i was given the impression that the cabinet dampening further added to the sound. thats what i was asking about. the driver itself i think should be fine. i heard a pair of enabled 127e's a few days ago and loved the higher registers...just perfect.

[BudP]

I agree about the 127's. I have a pair in Fonken boxes from Planet 10 denizens. This is the first speaker system I have ever had that I did not want to change, except that I added the subtle box treatment with painted blocks, rather than clear tape.

Treating the inside of the cabinet will provide benefit all out of proportion to what it should, for coherence from both the speaker and the port. Treating the cabinet face around the port and in the port and inside of the cabinet will also help with bass clarity and how many rooms away from the speakers folks complain about the bass from.

Adding mass for the entire column of compressed air to spring from will just aid the level of complaining.

I am not in charge of cookies around here, but you do get a thank you for being open minded enough to pursue getting treated speakers without requiring anti placebo indoctrination.

You really do want to discuss treating your room walls with Alex, by the way.....

Bud

[crappyjones123]

given my minuscule budget, i think the room treatments will have to wait for a few weeks/months.

as far as the anti placebo camp goes, i heard both stock 127e's and enabled 127e's in the same cabinet and there was a marked difference to my ears. for what its worth, the highs seemed a lot more tamed and not as harsh so my vote goes to the enabled drivers. the last time i heard the 206e's in a bib, they were a little peaky but not as bad as the 127e's.

any thoughts on question 1/3?

thanks,

cj.

ps. box treatments?

[BudP]

Treating the room walls can be done in a couple of hours, with self tacking, clear cabinet lining plastic sheeting, cut into appropriate sizes. Alex found that treating just the corners and only about 1/4 the way up the walls was particularly beneficial. Again, he is the expert in this.

1. Ask your builder to look for Automobile carpet underlayment, noise damping material. It is a composite of jillions of kinked fibers of differing lengths, thickness and materials, all compressed into a mat. This is the most linear sounding damping material I have ever heard and lends itself to EnABL very well.

2. Leave an area uncovered on all driver adjacent walls that is clear of damping material to the depth of the basket holes in the frame. Leave an area directly behind the driver, roughly the size of the driver, bare of damping materials. You should also ask them to apply the damping pieces in five alternating rows of material and clear surface, in vertical stripes up the side, front and back walls. The corners of the box should be covered with a central stripe. Leave the inner front wall bare of damping for as long a distance as it is from driver, across the front face and to the damping on the side walls. Have the damping on the inside of the top plate match the positioning of the damping on the sides, regardless of distance differences of driver to inner wall. There, that should be confusing enough..... Or, you could just EnABL the inner walls and have no damping.

3.Tunning the speaker to the cabinet and room and ear is going to take a lot of time. The more EnABL treatment the cabinet and room recieve, the less important this tunning will become. However. Use a single piano, recorded in a closed room, to do the heavy lifting here. After the piano quits sounding dull, you have removed enough damping from the wall surfaces. Then move on to a large choral group in a huge space, Mormon Tabernacle choir will do here. Add lead shot to the chamber you have decided on, or sand or whatever, until the balance between male and female voices is correct. Meaning you can hear emphasis from both, without it getting guttural or shrill respectively. Then move to a jazz combo with lots of drums and metal drum kit paraphernalia. Remove or add damping material to that space left open around the driver until rim shots, cymbals and drum heads are balanced and the decay of sound is natural in length and linear in decay rate.

Your EnABL'd drivers are going to allow you to fine tune your cabinet and the driver to perfection. You will know you are done when the sound puts you to sleep and you awaken refreshed. And, I really was not kidding about patterning the interior walls and minimizing the need for damping.

Bud