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

Thanks Dave. And over at the Ceinwyn thread Scott says that these cabs are not designed for high bass output. They cut off at 60Hz.

He also confirmed that a TH or TL type of sub would be suitable, sonically speaking.

The problem is that it partially defeats the elegance of simplicity; phase and sonic signature problems would arise.

Hence, I am for the time being dropping the idea of building a Ceinwyn and will try to simulate in HornResp a suitable MLTQWT for the Fostex168EZ drivers.

Dave and Scott, I really appreciate your benevolent contributions here. Thanks.
 
You're effectively trying to get a quart out of a pint-pot. The 168 is not a driver that is particularly good at producing frequencies below ~60Hz, short of being employed in a lengthy horn & it's not particularly at home in low-tuned mass loaded conical horns (ML TQWT) or straight mass loaded QWRs (MLTLs) unless a wad of Eq is employed. If you can't use a long horn (BIB, or something else -for e.g., they should do OK in Hiro down to the mid 40s, & people have employed them in a tweaked version of Ron's A166 which should be good for the same), which is what it's really been designed for, then you're probably going to be better off with a different driver.
 
Scottmoose said:
You're effectively trying to get a quart out of a pint-pot. 168 is not ... good at producing frequencies below ~60Hz, short of being employed in a lengthy horn ... they should do OK in Hiro down to the mid 40s
scott, you previously went over the above with me re: 166es-r and it helped me understand more of the concept. i finally have 4x8 void free plywood and can consider a Hiro. i'd like to know if the plans could or should be modified to better suite the 166es-r, i.e. any changes to the compression chamber, etc., etc.? measurements and specs can be found at zaphaudio dot com. thank in advance.
 
g chang v. sachiko

To get off topic somewhat, can someone tell me the difference between listening to a G Chang with Fostex 207E and the Sachiko with a 206E ? I built the G Changs several months ago and am very happy indeed with them . (Thanks Scottmoose and Dave. You are a pair of remarkably bright lads. ) Most builders seem to have gone for the Sachiko. Am I missing something? Have they seen something that I have missed? I listen mostly to jazz but my owner prefers classical. I prefer them to my Jordans, but then they are in very different rooms, so maybe that is not a fair comparison. Where did the double mouth design originate? Ieeoh
 
The double mouth configuration is a variation of ideas that stretch back at least as far as the 1930s. In recent times it was the late Terry Cain who brought this particular layout to wider attention in hi-fi circles (the pro-audio scene has been using W bins for decades of course).

I'm not sure if most builders have gone for Sachiko over the other cabinet or not -we've no way of knowing how many are out there. They offer different things. Sachiko has more gain and dynamic headroom; the Chang box provides a slightly smoother response and an easier build, while still offering a good sense of scale & decent control over the driver.

You prefer them to your Jordans? That's a result. :)
 
Jordan VTL transmission lines V. G Chang

Scottmoose. Thanks for your reply re the origin of the G Chang enclosure. As I had mentioned that I find the G Changs with Fostex 207e more enjoyable to listen to than the Jordan in the VTL transmission line enclosures, I thought that I should make an effort to compare like with like, at least as far as the surroundings go. I transferred my Jordan enclosures to the room in which I have the G Cs which is about 6.5m. square with concrete floors covered with carpet, building board walls and ceiling which is 2.4m. high. Not much soft furniture. There is just no contest between the two. The G Changs have greater clarity, musicality, accuracy of reproduction, clean realistic bass. The Jordans are OK and if I hadn't also built the G.Cs. I would probably have loved them.
I built the Jordan VTL transmission line enclosures exactly to the dimensions given on their site, but used MDF as I didn't then know that some of you think it is not a good material. What difference good ply would have made, I know not. For the G Changs I used two layers of 12mm particle board glued face to face and made allowance for the additional thickness to keep the original interior dimensions. I don't know all the audio type language that you audiophiles use but I really enjoy the G Changs. They seem to me to sound just as the original instruments would have sounded. I have Ray Brown playing now in the background. The really spectacular track that I often sit and listen to is on the "Montreux Alexander" CD. Track 4 "Worksong".
Don't know how you do it, Scottmoose and Dave. Is it the Yorkshire pudding and gravy?
 
Jordans enabled?

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.
 
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
 

Attachments

  • enabl posts for treatment text file.txt
    5.3 KB · Views: 83
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.
 
CJ

Having read your comment on preferred sound character, please read this thread.
http://www.diyaudio.com/forums/showthread.php?t=148911

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
 
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? :p

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.
 
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
 
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?
 
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