Thanks everyone for your replies. I suppose it's gratifying that I can trust my ears, old that they are. I'm also pleased that the padding I put behind the driver is a good thing - obviously I had done it for the Frugel Horns and had read here that reflections can come back through the driver so it seemed like the right thing to do. As I said in my earlier post, this peak is a minor irritant, most of what these speakers do is remarkably good.
Chris, thanks for chipping in with your expert view on these drivers. I have a friend over on Lenco Heaven who has a pair of the 7.3 metals. Interestingly we compared our drivers in Frugel Horn cabinets at a recent meet. He preferred his and I preferred mine, the power of ownership 😀 but general consensus was that the metals had a better top end, the papers had more lower down. Maybe I'll try and borrow his drivers.
XRK, the B80s you refer to - presumably this is the Visaton driver?
I have bought a little Dayton Audio iMM-6 mike and plugged it in to my android phone. I bought the Audio Tool app but I'm having trouble figuring out how to use it. I tried a pink noise file which gave me a graph but although I can store and reload the file it, it just doesn't show up on the files when I search for it on the laptop. In any case I really haven't a clue what I'm doing with this!
Cheers, Ian
Chris, thanks for chipping in with your expert view on these drivers. I have a friend over on Lenco Heaven who has a pair of the 7.3 metals. Interestingly we compared our drivers in Frugel Horn cabinets at a recent meet. He preferred his and I preferred mine, the power of ownership 😀 but general consensus was that the metals had a better top end, the papers had more lower down. Maybe I'll try and borrow his drivers.
XRK, the B80s you refer to - presumably this is the Visaton driver?
I have bought a little Dayton Audio iMM-6 mike and plugged it in to my android phone. I bought the Audio Tool app but I'm having trouble figuring out how to use it. I tried a pink noise file which gave me a graph but although I can store and reload the file it, it just doesn't show up on the files when I search for it on the laptop. In any case I really haven't a clue what I'm doing with this!
Cheers, Ian
Yes, Visaton B80. Available from Solen in U.S./Canada. I want to try that iMM-6 mic too but don't have one yet so can't help you.
If you can get your friend's metal A7 that would be helpful in determining if you like the sound better.
If you can get your friend's metal A7 that would be helpful in determining if you like the sound better.
I've finally decided to try my skills at foam-core by making a variant of this design with Alpair 7.3 as cornu seems to be a little hardcore for a first-timer 🙂
I want the enclosure to be rectangular, like in this design:
http://www.diyaudio.com/forums/full-range/231951-accidental-mltl-technique-16.html#post3466655
Can somebody explain how is the line length calculated? It looks like measurements are done by drawing a straight line which lies in between walls. Does the fold count affect it in some way?
I want the enclosure to be rectangular, like in this design:
http://www.diyaudio.com/forums/full-range/231951-accidental-mltl-technique-16.html#post3466655
Can somebody explain how is the line length calculated? It looks like measurements are done by drawing a straight line which lies in between walls. Does the fold count affect it in some way?
You could do it like this by earlier post:
Regarding line length - draw lines from inside corner to outer vertex and make TL length pass through the mid point on all corners. This is close to the TL effective length. A 180 deg hairpin turn equals 4 segments of 45 deg wedges. Typically for uniform line width the midpoint length is half the width per 45 deg segment.
Thanks X, very helpful as always 🙂
I wanted to minimize the footprint as wall space is limited, so I'll stick with square prototype for now, just to compare with BR that I'm using now.
I wanted to minimize the footprint as wall space is limited, so I'll stick with square prototype for now, just to compare with BR that I'm using now.
This is a surprisingly compact speaker that takes no desktop space at all if wall mounted. I brought it to the office for my PC speaker and sounds great there.
X, have you removed that BSC filter you mentioned earlier? Which tube length are you using now?
The pic a couple of posts up is mine, based on XRK's design. It works very well and has a delightful synergy with the little SMSL 36A Pro amp making an excellent study system for not much money. Thanks again XRK.
Ian, have done any measurements? It looks like you are using suggested 4inch / 10cm tube. I will probably make that adjustable for my first prototype, but some starting point is still needed 🙂
I can't remember the exact measurements but basically I kept the same lengths above and below the driver as XRK's plans and simply folded it slightly differently. I did put some sound absorbing felt behind the drivers which I think helps. Good luck!
I started at 4in but tuned it to 1.5in in the end by. Adjust to taste - a telescoping tube would be good. I am not using BSC when wall mounted it seems to have good balance. The SMSL 36A is also what I used at first. Now switched to TDA7297. Both great amps but I don't need as good of an amp for mono duties at work. Plus BTL class D can't be tied together for mono via two resistors.
Nice build - what I noticed was that the SQ was better with a shorter vent vs longer. About 1.5in long brought the bass volume higher. What don't you like about the sound vs an equivalent BR? It should have less baffle step than a smaller prismatic box of same volume.
BR has way more bass, but maybe it has something to do with how I attached the top (front) layer. I've used black silicone, which I've also smeared between side walls and front/back panels. Inner parts are glued with hot melt. The good thing about silicone is that I was able to remove the top easilty by cutting and peeling it off. Next time I'll probably add a paper layer beneath the top and glue it with PVA. I'll do some proper measuruments as well.
Anyhow, that's quite an acceptable result for the first time. Next stop - 50cm cornu 🙂
Anyhow, that's quite an acceptable result for the first time. Next stop - 50cm cornu 🙂
Sounds like you may have had a pinhole leak on the inner channel - that will collapse the 1/4-wave and reduce bass.