I'm playing with the stuffing on some el cheapo Bibs made from 18mm white kitchen type chipboard using CSS FR125s drivers. They are now stuffed to level 2here
The boxes are extensively screwed together and sealed rather than glued as I have a lack of clamps. Also I was concerned the glue wouldn't take to the laminate surface well, so screws won the day. I know the design maths relates to BB ply, but the budget wouldn't run to it unfortunately.
Overall I am extremely pleased by the sound, the drivers having been in 9 litre ported MDF boxes for a couple of years before.
The only issue I am having is the very top end of the sound is lacking. It's the delicate cymbals and "breathyness" type of frequencies that are missing from the sound I was getting from the bass reflex boxes. The bass however is much more present and immediate than previously. This is using the same amp and source as before.
Could this be more stuffing required, the inferior materials used, or is it an unavoidable trade off for the increased bass output I am now revelling in?
The back of the baffle is relieved around the driver but could go out further if it would help. I'm using a double baffle to space the driver from the internal divider, this could also be bellmouthed more.
The plan is to vinyl wrap them once all the tuning is done to tone down the fridge look and hide the raw edges. I have some grille cloth for over the tops, it's a long reach when something drops in there!
Absolutely none of this is a criticism of the Bibs, the sound is splendid but if I can get the fine detail back it would be the cherry on the cake for me.
Many thanks to all involved in developing this design, it's brought a huge grin to my face every time I've sat down between them.
John
The boxes are extensively screwed together and sealed rather than glued as I have a lack of clamps. Also I was concerned the glue wouldn't take to the laminate surface well, so screws won the day. I know the design maths relates to BB ply, but the budget wouldn't run to it unfortunately.
Overall I am extremely pleased by the sound, the drivers having been in 9 litre ported MDF boxes for a couple of years before.
The only issue I am having is the very top end of the sound is lacking. It's the delicate cymbals and "breathyness" type of frequencies that are missing from the sound I was getting from the bass reflex boxes. The bass however is much more present and immediate than previously. This is using the same amp and source as before.
Could this be more stuffing required, the inferior materials used, or is it an unavoidable trade off for the increased bass output I am now revelling in?
The back of the baffle is relieved around the driver but could go out further if it would help. I'm using a double baffle to space the driver from the internal divider, this could also be bellmouthed more.
The plan is to vinyl wrap them once all the tuning is done to tone down the fridge look and hide the raw edges. I have some grille cloth for over the tops, it's a long reach when something drops in there!
Absolutely none of this is a criticism of the Bibs, the sound is splendid but if I can get the fine detail back it would be the cherry on the cake for me.
Many thanks to all involved in developing this design, it's brought a huge grin to my face every time I've sat down between them.
John
Attachments
No ideas out there?
I carried on adding stuffing down the throat and tamping it down to see what would happen. It took another bag of it for the bass output to become too weak.
The overall sound improved to a point as it was added though, so I thought I might be onto something.
Off came the baffles again to increase the density of the stuffing in the closed end and fish the excess stuffing from the fold. Screws have their advantages for the short armed newcomer.
While the baffles were off I improved on the bellmouthing round the back of the driver, it was too tight before if I'm honest.
While the bibs were apart I put the drivers back in the ported boxes, to make sure I was remembering the true sound of them. After a couple of weeks of bib listening the ported boxes suddenly sounded very very weak indeed, nowhere near as good as I was remembering them. Rose tinted ears maybe?
The end result is a great improvement in clarity, I am hearing new details in tracks I have heard dozens of times. Drums sound tremendous, nothing is too fast for them and voices are splendid! Bass is simply in another league to the old boxes or anything I've ever heard.
All told, I am delighted with them. Even from sub standard materials they sound great, I should try some in BB one day. They came in at about £45 less the drivers and make me smile just walking past them!
John
I carried on adding stuffing down the throat and tamping it down to see what would happen. It took another bag of it for the bass output to become too weak.
The overall sound improved to a point as it was added though, so I thought I might be onto something.
Off came the baffles again to increase the density of the stuffing in the closed end and fish the excess stuffing from the fold. Screws have their advantages for the short armed newcomer.
While the baffles were off I improved on the bellmouthing round the back of the driver, it was too tight before if I'm honest.
While the bibs were apart I put the drivers back in the ported boxes, to make sure I was remembering the true sound of them. After a couple of weeks of bib listening the ported boxes suddenly sounded very very weak indeed, nowhere near as good as I was remembering them. Rose tinted ears maybe?
The end result is a great improvement in clarity, I am hearing new details in tracks I have heard dozens of times. Drums sound tremendous, nothing is too fast for them and voices are splendid! Bass is simply in another league to the old boxes or anything I've ever heard.
All told, I am delighted with them. Even from sub standard materials they sound great, I should try some in BB one day. They came in at about £45 less the drivers and make me smile just walking past them!
John
john blackburn said:
In my limited understanding of psycho-acoustics (and confirmed by listening experience), the ear often perceives an excess of one frequency range as a deficit in another, and vice versa. Basically, too much bass can sound like too little treble. Too much treble can sound like too little bass. I think your lack of detail was indeed the result of too much bass.
I have found, as you did, that unstuffed BIB's can produce more bass than most anyone needs. I've had pretty good luck with stuffing mine, but it sounds like one can stuff too much overall, or stuff in the wrong place, and make the whole speaker sound "dead".
I've also found that ears can be awfully adaptive. Sometimes you need to listen for a couple of weeks before you know what you've got. I bet you were used to the sound of too little bass and too much treble (probably no BSC on the ported boxes, right?). The BIB's may have swung too far in the other direction, but it was certainly the opposite of what you were accustomed to.
It sounds like you've got things well sorted.
I, like you, went from drivers in ported boxes to the BIB's. And like you, when I put the drivers back in the ported boxes, I was surprised at how anemic they sounded.
BIB's are special. If you ever get the urge to improve both the looks and sound, you could consider gluing a nice looking 1/4" ply over the top of the chipboard. It would stiffen the panels quite a bit and provide a nice veneer to finish. Chipboard is not resonant, but if you stiffen it up, you may find even more bass!
pj
www.wildburroaudio.com
>>> It's the delicate cymbals and "breathyness" type of frequencies that are missing from the sound...
Add an inexpensive piezo super tweeter to the rear along with an Lpad for tuning and you will add all the sparkle your heart desires.
http://www.zillaaudio.com/fostex-165k-bib.htm
http://www.zillaaudio.com/tb-1320-bamboo.htm
http://www.zillaaudio.com/pioneerb20-piezo.htm
Only the B20/piezo has the Lpad but it helps in tuning the sound.
I'd use a 1 or 1.5uf cap to start (along with a 8 or 20ohm resistor) and add the L-pad. Contact me if you need the stuff and i will see what i can do. Godzilla3@hotmail.com
Just my opinion... but i like rear firing tweeters with full/wide range drivers.
Godzilla
Add an inexpensive piezo super tweeter to the rear along with an Lpad for tuning and you will add all the sparkle your heart desires.
http://www.zillaaudio.com/fostex-165k-bib.htm
http://www.zillaaudio.com/tb-1320-bamboo.htm
http://www.zillaaudio.com/pioneerb20-piezo.htm
Only the B20/piezo has the Lpad but it helps in tuning the sound.
I'd use a 1 or 1.5uf cap to start (along with a 8 or 20ohm resistor) and add the L-pad. Contact me if you need the stuff and i will see what i can do. Godzilla3@hotmail.com
Just my opinion... but i like rear firing tweeters with full/wide range drivers.
Godzilla
Thanks both, I think you've both hit the nail on the head.
You were right about the lack of baffle step compensation, the bibs are only my second build so I was just glad they made sound at all.
They dont need sparkle, but I thought I did, if you see what I mean. The sound from the latest state is very natural, I think it's time to sit and enjoy them for a bit before any decisions are made. Nina Simones piano can manage to be intimidating but I suspect that's just the way she played it!
I went from a set of Bose 2 ways a friend gave me to the ported boxes and now to the bibs, progress indeed.
Thanks chaps
John
You were right about the lack of baffle step compensation, the bibs are only my second build so I was just glad they made sound at all.
They dont need sparkle, but I thought I did, if you see what I mean. The sound from the latest state is very natural, I think it's time to sit and enjoy them for a bit before any decisions are made. Nina Simones piano can manage to be intimidating but I suspect that's just the way she played it!
I went from a set of Bose 2 ways a friend gave me to the ported boxes and now to the bibs, progress indeed.
Thanks chaps
John
BIB Stuffing
Having mostly completed one pair of BIB's, I am no expert, but thought I would share my experience.
Scottmoose advised me to start with some felt carpet underlay. I was not able to find the real wool type, but did not get the rubbery stuff. Scott said to line the front of the divider board, from a few inches below the driver, up to the top of the first chamber of the horn. Beside the front of the divider board, he said to line one side, also from below the driver to the top. I have never changed that part.
I listened to Bob Hodas speaking at VSAC. See http://www.bobhodas.com/ He talked about stuff he used made from ground up Levis. See http://www.acousticalsurfaces.com/
I contacted them to see what a small amount would cost. They just sent me a few scraps for free. I put some at the very bottom of the speaker, and just behind the driver. I liked what it did!
I had hoped someone would "give me the recipie" but ended up spending many hours over time, adding and then subtracting stuffing matierial. I may not have ended up where someone else would, but the advantage spending the time, is that I don't have to wonder if I should have had more, or had less. I feel like I found what worked best for me, in my room, with my speaker.
Hope this helps in some way.
If anyone would like to further enlighten me, feel free! I am planning to finally finish my BIBs and seal them up for the last time within the next few days or so.
Sincerely,
Benjamin
Having mostly completed one pair of BIB's, I am no expert, but thought I would share my experience.
Scottmoose advised me to start with some felt carpet underlay. I was not able to find the real wool type, but did not get the rubbery stuff. Scott said to line the front of the divider board, from a few inches below the driver, up to the top of the first chamber of the horn. Beside the front of the divider board, he said to line one side, also from below the driver to the top. I have never changed that part.
I listened to Bob Hodas speaking at VSAC. See http://www.bobhodas.com/ He talked about stuff he used made from ground up Levis. See http://www.acousticalsurfaces.com/
I contacted them to see what a small amount would cost. They just sent me a few scraps for free. I put some at the very bottom of the speaker, and just behind the driver. I liked what it did!
I had hoped someone would "give me the recipie" but ended up spending many hours over time, adding and then subtracting stuffing matierial. I may not have ended up where someone else would, but the advantage spending the time, is that I don't have to wonder if I should have had more, or had less. I feel like I found what worked best for me, in my room, with my speaker.
Hope this helps in some way.
If anyone would like to further enlighten me, feel free! I am planning to finally finish my BIBs and seal them up for the last time within the next few days or so.
Sincerely,
Benjamin
Hi Benjamin.
Thanks for that. I am using soft toy stuffing fibre in mine, I saw the carpet underlay recomendation but couldn't get the wool felt round here. I know what you mean about spending many hours at it. The room I was using ended up with bits of white fluff everywhere, looked like a Santa hat factory.
A mate has a pair of Kef Corelli speakers that have suffered child finger trauma to the tweeters. I am ordering him a pair of Vifa replacements soon as he has no internet access. When they are delivered I am going to mount them on the rear of my Bibs for a few days just to see what happens. Now I am getting used to the sound it may make them too bright, we will see. Just proves that what I think I want isn't always what I need.
Bob Hodas has a diverse recordings list and no mistake, The Village People and Pope John Paul. Hopefully not at the same time!
John
Thanks for that. I am using soft toy stuffing fibre in mine, I saw the carpet underlay recomendation but couldn't get the wool felt round here. I know what you mean about spending many hours at it. The room I was using ended up with bits of white fluff everywhere, looked like a Santa hat factory.
A mate has a pair of Kef Corelli speakers that have suffered child finger trauma to the tweeters. I am ordering him a pair of Vifa replacements soon as he has no internet access. When they are delivered I am going to mount them on the rear of my Bibs for a few days just to see what happens. Now I am getting used to the sound it may make them too bright, we will see. Just proves that what I think I want isn't always what I need.
Bob Hodas has a diverse recordings list and no mistake, The Village People and Pope John Paul. Hopefully not at the same time!
John
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