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10" mid bass horn |
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doober 
Young Croc 
Joined: 03 January 2006 Location: Cornwall UK Status: Offline Points: 1118 |
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 Topic: 10" mid bass hornPosted: 15 January 2009 at 9:44am |
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Thanks chaps
The folding was always going to be a compromise, but seemed like the best way to fit a long horn in a short box. The use of 4 seperate sections around the bends should help to reduce ill effect. I remember years ago people were using 15" w bins up to 500hz, my version should certainly be an improvement on that. I really should press on with the 6" horn for above sometime. Kieran |
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Autograff
Young Croc
Joined: 22 October 2008 Location: Sheffield , UK. Status: Offline Points: 1361 |
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Posted: 14 January 2009 at 11:51pm |
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Well Done !
Not even heard it and i want some
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RosscoPico
Young Croc
Joined: 31 January 2007 Location: Brighton, UK Status: Offline Points: 955 |
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Posted: 14 January 2009 at 10:46pm |
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Give yourself a big pat on the back man, it's really great to see that you attempted such an interesting and pretty radical design (without CAD I must add!) and have pulled it off successfully, at least in terms of construction anyways Am also intrigued to see how your tops come out, am looking forward to that! |
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.:ELEMENT 5 SYSTEMS:.
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doober
Young Croc
Joined: 03 January 2006 Location: Cornwall UK Status: Offline Points: 1118 |
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Posted: 12 December 2008 at 5:24pm |
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A brief update-
I've had a good listen at low to moderate levels in the garage, with a 15" reflex below and a 12"+1" reflex above. I started with 90hz hpf and 400 hz lpf, time alingnment done with a dcx auto align. It sounds pretty good, blended in with the other cabs very well. Bass guitar comes across very nicely, breakbeat loops sound great. I tried all sorts of music including D&B, mid 90's hardcore, Manu Chao, KT Tunstall, Pixies, New Model Army, Bad Manners, S Club 7 (oh yeah!), and any other randomness I had on the laptop. I took the upper freq up to 500hz and it still sounded fine from a distance, although close up (ie in the horn mouth) there was a noticable honk at the upper end, particularly on male vocals. When I took it back to 400hz I could still detect this (sounded like listening through a tube on some notes), but it wasn't audible a couple of metres away. I need to try this same setup somewhere away from other people and see if the honk is audible at greater distances with higher power levels. It certainly seems like i'll get away with using it up to 400hz. I've started calculating the 6" horn to go above, this should be happy down to around 300Hz, so I'll have some room for manouvre. Kieran. |
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doober
Young Croc
Joined: 03 January 2006 Location: Cornwall UK Status: Offline Points: 1118 |
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Posted: 05 December 2008 at 3:40pm |
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Driver is currently an old Zomax 10", I don't have any accurate t/s parameters for it, I happen to have a few of them so I thought i'd try it for now.
It's got a big magnet and the suspension feels quite tight, my attempts at measuring the t/s gave quite odd results. I plan to try Beyma 10g40 and 18sound 10mb600 at some point. |
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overdrive
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Joined: 13 July 2004 Location: Netherlands Status: Offline Points: 21 |
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Posted: 05 December 2008 at 11:56am |
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Nice build! What kind of driver are you using?
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doober
Young Croc
Joined: 03 January 2006 Location: Cornwall UK Status: Offline Points: 1118 |
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Posted: 04 December 2008 at 8:55pm |
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Thanks mobiele eenheid, I really should have known that.
Next question- how do I accurately measure the power going in, do I use a sine wave at a frequency of known impedance? bandpass filtered pink noise? something else? This is all a bit more precise than my old favourite method of just having a good listen (although I'll do that as well of course.) |
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mobiele eenheid
Old Croc 
Joined: 15 August 2004 Location: Netherlands Status: Offline Points: 1568 |
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Posted: 04 December 2008 at 5:34pm |
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100 W (28,28 V@8Ohm)/ 10 metre is common because it's closer to real life use. To calculate any distance you can take the 10*log of the input power. I.e. 10*log 1 = 0, 10*log 500 (W) = 27 (dB).
Best regards
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doober
Young Croc
Joined: 03 January 2006 Location: Cornwall UK Status: Offline Points: 1118 |
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Posted: 04 December 2008 at 5:07pm |
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It weighs about 30kg at the moment. This will change when I use 15mm ply instead of 18mm chipboard for the outside, and 12mm ply instead of 12mm mdf for the initial horn. The rest will stay as is, 12mm ply. I will need some extra bracing on the side panels, there's a fair bit of resonance at high power levels. the box also needs to be 20cm taller to allow for the 6" mid horn above. I'm hoping it will be a one man lift when finished, so <50kg is the target, not bad for a 3 way fully horn loaded box.
The spl is calibrated, the input level is not. I'll do some more accurate plots when I try some different drivers. Could anyone remind me how to do a plot for 1w/1m at a greater distance, ie how to calculate input power to compensate for 6db spl loss per doubling of distance? |
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tommysb
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Joined: 24 April 2006 Location: Finland Status: Offline Points: 1036 |
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Posted: 04 December 2008 at 10:11am |
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Are those plots calibrated?
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davey t
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Joined: 11 March 2004 Location: Bristol UK Status: Offline Points: 1428 |
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Posted: 03 December 2008 at 10:41pm |
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looks amazing! I've been thinking through 10" or 12" low mid wbin-esqe design but you have put the effort in and taken it to the next level! definately beats bill fitz's tops.
How heavy did it turn out? those wood pieces seem pretty thick. Try taking a plot with the mic in line the horn mouth |
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Minirig portable soundsystem movement
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doober
Young Croc
Joined: 03 January 2006 Location: Cornwall UK Status: Offline Points: 1118 |
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Posted: 03 December 2008 at 6:01pm |
Hmmm, next project perhaps
I tried another plot in slightly better conditions, but left the mic a bit high off the ground (oops), resulting in a loss higher up. 
Looks a lot smoother now. I'll try some measurements in a field when I sort out a decent inverter or quiet generator. In the meantime I'm confident it'll do what I want in terms of FR, it's time for some extensive listening tests next. I need to try a few tweaks here and there but I'd rather leave this until I've built another one so I can do a/b comparisons. The next one will be made from decent ply and hopefully will eventually be the full 10" 6" 1" box. It's nearly time to work out a starting point for the 6" section and see how I can package it all neatly. Kieran. |
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My only question mark would be using folds for higher frequencies but despite that, I'd sure like to have a listen to your impressive prototype! I admit that when I first saw the mid-construction photo you had put up on the compound angles thread it sure had me thinking WTF is that?!
Deadbeat wrote: