There is a 45 degree pad under the driver on the ID horns...that should allow the wavefront to realign pretty well, and any null points are way up in the FR since the distance is very small.
ID built me a set of straight entry horns that I have been using for the last 6 years. They are larger than the regular horns...and Eric didn't feel as if people would want to give up even more space to use them. But the molds are there to make them.
I built a set of 1/4 sized 250 hertz exponential horns for a 2" driver this past winter. Looked like a giant ID horn (should since Eric helped me out with them). Ended up not using them, but building the mold, then the plug, and laying a pair of them up was a fun learning experience.
Your moldds look pretty good.
Can't wait to see what you think about them. And if you wanted to build a set of 1.5" drivers, I have some super nice Beyma CP 755Nds that you could try out (going to use them in my car) that should get you down to 450 in the car and all the way out to 20k with real treble.
ID built me a set of straight entry horns that I have been using for the last 6 years. They are larger than the regular horns...and Eric didn't feel as if people would want to give up even more space to use them. But the molds are there to make them.
I built a set of 1/4 sized 250 hertz exponential horns for a 2" driver this past winter. Looked like a giant ID horn (should since Eric helped me out with them). Ended up not using them, but building the mold, then the plug, and laying a pair of them up was a fun learning experience.
Your moldds look pretty good.
Can't wait to see what you think about them. And if you wanted to build a set of 1.5" drivers, I have some super nice Beyma CP 755Nds that you could try out (going to use them in my car) that should get you down to 450 in the car and all the way out to 20k with real treble.
winslow said:
In the previous car I went the same route, trying to stretch the bandwidth of a compression driver as far as humanly possible. Started with a cheap 1" Selenium, then progressively moved up the ladder to bigger and badder compression drivers. I tried a 1" B&C, a 1" Radian, then lucked out and stumbled across the mighty JBL 2470. The JBL 2470 is one fantastic driver (once you replace the crappy phenolic diaphragms.) But I still couldn't get it to work as well as the Unity.
As you go with a bigger compression driver, your top end suffers; this is inevitable. You can throw a lot of money at the problem, but you're still facing the law of diminishing returns.
Compared to my mighty JBLs, my former Unity project had a delicacy to the treble that the JBLs could never match; they just couldn't play as high as the neo BMS can. And the JBL 2470 could play below 1khz with authority in a way the BMS never could, but once you add the midranges into the Unity horn, it's GAME OVER.
Unity wins.
Admittedly, it's a LOT of work, but the results were amazing last time around, and this time I'll fix all the mistakes I made in 2006.
You mentioned that you would be willing to provide casts of your mold. I'd be down for a pair. Let me know how much and where to send the payment!
What would be the effects of incorporate a 90 degree elbow on the throat of the horn for the compression driver? I'm pretty sure the whole waveguide will not fit on my dash without modifying the placement of the drivers.
What would be the effects of incorporate a 90 degree elbow on the throat of the horn for the compression driver? I'm pretty sure the whole waveguide will not fit on my dash without modifying the placement of the drivers.
You will create null points further down in the FR the further you get away from the driver.
I think John is shooting for 400-1k in his setup with the midranges.
I wonder what the overal sensitivity of the design will be? The compression driver is really up there, but the midranges are not.
I think John is shooting for 400-1k in his setup with the midranges.
I wonder what the overal sensitivity of the design will be? The compression driver is really up there, but the midranges are not.
winslow said:
According to horn response, efficiency will be over 100db on the midranges.
http://www.diyaudio.com/forums/showthread.php?postid=1430391#post1430391
The big flaw last time around was that the midrange enclosure was all F'd up. The efficiency on the mids in 2006 was only around 85db. Take a look a the first page of this thread for measurements. So in 2006 I'd tweaked the crossover to deliver a flat response with the mids, but the entire midrange enclosure was all wrong (it was way too big.)
This time around, we'd be lucky to hit 120db if they only handled 10 watts each, but power handling goes up in a huge way when you horn load them. I bought two boxes(!) full of midranges on the assumption I'd blow some, but I haven't popped one yet. I'm using an amplifier that puts out 400watts into 4ohms. The mids are something like a seven ohm load at the moment. (That will change; I'm adding a third on each side.)
omarmipi said:
My plan is to just knock out a bunch of waveguides. Won't be creating another mold, I HATE MAKING MOLDS
I've made two waveguides so far, they're drying right now.
I'm giving them a few days since fiberglass shrinks.
Found that out the hard way one time, took the waveguide off the mold too soon and it simply collapsed as it dried.
omarmipi said:
From everything I've read, putting any kind of bend in a waveguide is a BAD IDEA. Based on what I know, even a dimple that's a millimeter across can ruin the throat; now imagine if you're introducing a ninety degree bend that's an inch long?
We're talking full-on disaster here.
One thing I've considered, and this is a big "if" -
It *might* be ok IF there's ZERO expansion.
I'll ask Geddes and find out.
Patrick Bateman said:
QUestion answered: http://www.diyaudio.com/forums/showthread.php?postid=1557476#post1557476
I just printed out the pages for making a mold...really want to give these a try. May give it a go with the Selenium driver over the BMS since the Selenium is less than half the price of the BMS and only a touch larger.
Let me know if you want to make another pair. Be glad to paypal you some fundage...especially so I don't have to make the mold.
Let me know if you want to make another pair
. Be glad to paypal you some fundage...especially so I don't have to make the mold.
winslow said:I just printed out the pages for making a mold...really want to give these a try. May give it a go with the Selenium driver over the BMS since the Selenium is less than half the price of the BMS and only a touch larger.
Let me know if you want to make another pair
Yes, I'll do extras
winslow said:I just printed out the pages for making a mold...really want to give these a try. May give it a go with the Selenium driver over the BMS since the Selenium is less than half the price of the BMS and only a touch larger.
Let me know if you want to make another pair
I don't know wtf is up with Assistance Audio (the U.S. distributor of BMS.)
I purchased my compression drivers from him about four years ago, but have never been able to buy anything else. I've tried on three occasions to buy more stuff, and he never returned my emails or phone calls.
I even tried going through usspeaker, even though they cost 20% more... only to find they're buying from Assistance Audio.
So if anyone knows a way to get their attention, I'd love to know.
IMHO, the BMS is superior to the Selenium. It's smaller, has less distortion, and the price difference is a lousy twenty bucks. IF you can get it.
http://www.aalse.ru/D2500TiNd.pdf
http://www.auraaudio.fi/Pdf/BMS/bms-4540nd.pdf
Can't help you there...I've tried the last couple of years to get a hold of Assistance Audio with no luck. The other BMS guys like Martinelli Sound have stopped selling BMS too.
The BMS from US Speaker is about $120 each, whereas I can get the Selenium for less than $70 each from Parts Express (have a buddy with a wholesale account there). $100 savings is a big deal to me. Especially considering that if something happened, I could get the Selenium fixed.
The BMS from US Speaker is about $120 each, whereas I can get the Selenium for less than $70 each from Parts Express (have a buddy with a wholesale account there). $100 savings is a big deal to me. Especially considering that if something happened, I could get the Selenium fixed.
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