In order to reach the same CC volume as the Fostex RecEnc you would have to shut the CC 6cm inwards; then you will have ˜1.55 litres, which is splendid for the little guy. Making it larger will make it sound "hollow" and give you phase problems. I have an even smaller CC, but it matches my room acoustics.
Best,
Oliver
Best,
Oliver
coredump said:
Be wary of making it too small. Chris & i tried the some found appropriate in earlier posts and found we prefered the original size... Bob scooped the B-Horns up before we had a chance to play with volumes in between. If you are going to muck with the CC, i'd be inclined more to change its ahape (more trianular) and easy access to be able to add "bricks" to play with its volume.
Are you aware of this thread?
http://fullrangedriver.com/forum/viewtopic.php?id=53
dave
Dave,
From the back of my head; did you take out the stuffing? AFAIK you tested a small CC with felt inside, etc. (that's what I gathered from Chris' posting then, I may be wrong though). I am advocating a (relatively) small CC with no stuffing at all, in order to give the driver an 'undistorted' impedance. My reasoning is: if the impedance is right for the driver, you don't need any stuffing. My Bicors have no stuffing in them, either, and (to my ears) they sound just dandy.
Of course I'm absolutely with you concerning CC shape, and I agree that a more modular approach would be better.
But I would strongly advise against trying to increase the CC (Kofi asked this), as one would have to re-design the horn somewhat. I'd rather create a wider baffle (following Ron's advice here), perhaps using disks to mount the drivers, as used by you-know-who with his Abbys.
Thanks for the hint, but yes, I have posted on it, too. ;-)
Best,
Oliver
From the back of my head; did you take out the stuffing? AFAIK you tested a small CC with felt inside, etc. (that's what I gathered from Chris' posting then, I may be wrong though). I am advocating a (relatively) small CC with no stuffing at all, in order to give the driver an 'undistorted' impedance. My reasoning is: if the impedance is right for the driver, you don't need any stuffing. My Bicors have no stuffing in them, either, and (to my ears) they sound just dandy.
Of course I'm absolutely with you concerning CC shape, and I agree that a more modular approach would be better.
But I would strongly advise against trying to increase the CC (Kofi asked this), as one would have to re-design the horn somewhat. I'd rather create a wider baffle (following Ron's advice here), perhaps using disks to mount the drivers, as used by you-know-who with his Abbys.
Thanks for the hint, but yes, I have posted on it, too. ;-)
Best,
Oliver
planet10 said:
Thanks!
OK-- got it. I'm too stupid to do the triangular CC, so I'm going to make it stat and add "bricks" as necessary.
Also, I wanted to make the angle cuts at the initial cut of the wood, so I started to use some trigonometry to divine the angles I'd need to cut. After remembering that I suck at triginometry, it dawned on me that someone would know the correct angles for the internal cuts. Anyone got these?
If not, should I just go the trial-and-error route and cut / file a little bit off at a time until the angle is right? Or should I go back to trig?
Oh, why did Stacey Altebrando have to be in my 5th period trig class? And why did her Mom buy her sweaters that were two sizes too small? I coulda learned trig, you know, but its not my fault. However, if anyone wants to know Stacey Altebrando's weekday sweater rotation, please let me know. I memorized it.
A little help?
Kofi
It was really more of a volume calculation... geometry.
Gotta love Dave! But not in a like-I-love-Mrs.-Annan way! You know what I mean! Thanks!
I've been experimenting with stain on MDF and I think I'm getting the hang of it. I've been using a deep red stain / poly combo and I'm starting to get some pretty good looking practice boards. I know, I know... shouldn't stain MDF, but I like the look and I'm using a really deep red stain so its sort of covering up the fact that its MDF.
I'll start cutting the angles tonight, but I gotta get a sheet of 5/8" (16mm) MDF for the sides and front today.
Thanks again for all the help.
Kofi
planet10 said:
Hey man, the Annans ain't made of money. I suppose if I lived in Canada I could just go outside, chop me down a baltic birch, cut it down on my sawmill and get to work. For Secretary Generals of the United Nations that live in Atlanta like me, our baltic birch ply comes from a little place we call Atlanta Wood Products and they work on the basis of cash money.
Baltic birch ply costs significantly more than your average MDF, and Mrs. Annan and I are about to be broke, so I need to keep my hobby alive here.
I know that I am breaching the tenets of the DIYAudio community, but I need to save money and still get my audio on. I used to throw financial caution to the wind on audio projects, but I have some reasonably heavy financial commitments on the horizon, so I need to save where I can.
Don't mock me. I was once like you.
Kofi
Kofi Annan said:
A sheet of BB should be like $50 vrs $25 for MDF. Given the cost of the haircut requred to cover up the hair pulling if you build MDF it is a bargoon. The difference is WAY more than the difference in cost. Just forgo Latte's for a couple days (or leave that bottle of Scotch on the shelf and drink water)
dave
Lattes? Sorry, but I'm a REAL man. Only Cafe Au Laits for me. That's of course when I don't have pilates in the morning...
You know, I built the Swans out of baltic birch and I have noticed that I really "hear the box" when I'm using them. I initially thought that this was because I used plywood for the first time instead of MDF. Based on our earlier discussion, I know that the D101a Swans probably need a compression chamber enlargement to accommodate the 108EZs, so that is also a likely culprit.
So, given my experience with the baltic birch on the Swans, what sounds better about the plywood over the MDF and why? I could be convinced that I need to splurge on the BB, but I need to buy a sheet of 1/2" AND a sheet of 5/8" for the set, which means I gotta justify the cost to Mrs. Annan.
Thanks again for all the advice. Please don't yell at me again. My Dad used to yell at me. "Kofi! Clean the kitchen! Kofi! Take out the trash! Kofi! Make those out of baltic birch!"
That's funny. I'd love to, but my other hobby is alcoholism. Now how would that sit with my compatriots on DIYAlcoholism.com? Planet 12-year-old-scotch would likely issue a <strong opinion> about your suggestion.
Kofi
OK-- finished the cuts yesterday and I'm ready to assemble using the aforementioned controversial material. Some questions:
I've seen people fill the two triangular holes with sand, but I'd like to know if that's worth it or not. Also, do you just dump in some sandbox-type sand and close 'er up or is there a trick to it? Also also, would river rock work?
And more...
Concerning stuffing, I was thinking I'd use Dacron in the compression chamber and maybe some felt in the throat. Any advice on this?
Kofi
I've seen people fill the two triangular holes with sand, but I'd like to know if that's worth it or not. Also, do you just dump in some sandbox-type sand and close 'er up or is there a trick to it? Also also, would river rock work?
And more...
Concerning stuffing, I was thinking I'd use Dacron in the compression chamber and maybe some felt in the throat. Any advice on this?
Kofi
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