P.Audio SD-450 N on JBL 2370 Bi-Radial Horn with Wayne Parhams compensation circuit [message #40378] |
Sat, 22 February 2003 21:02 ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Adrian Mack
Messages: 568 Registered: May 2009
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Illuminati (1st Degree) |
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Hey everyone. I'm thinking of using either the P.Audio SD-450 N or BM-D440 compression driver on a JBL 2370 Bi-Radial Horn. I would use Wayne Parham's compensation circuit after reading a lot of posts from him it looks like it works pretty good. Just wondering if I will recieve any troubles with this, or if the P.Audio's are really the ones to use or not. P.Audio stuff is pretty expensive in the USA, but here in Australia it is priced a lot better :) and theres not really any range available in australia and I would like to steer clear of orderering from the US because of high shipping prices. I can get the JBL 2370 bi-radial horns for AU$50 a piece (so about US$25 each ) which is pretty good to me. My goal is a smooth response, high efficieny, with wide dispersion and good clarity. I've also considered building a bi-radial horn myself from wood after reading an article found here http://www.woodhorn.com/horn.htm that describes how. When making the horn, how do I construct it fr say 90 x 40 degree dispersion? Is it that the angles have to be 90 and 40 degrees, or is there more to it than that? Are radial and bi-radial horns the same thing? Thanks in advance for any type of feedback.... even if you dont know what your talking about anything would be cool :)
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Radial horns [message #40380 is a reply to message #40378] |
Sat, 22 February 2003 23:50 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18750 Registered: January 2001
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Illuminati (33rd Degree) |
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Radial horns are those that are extruded along the horizontal axis to form a "pie slice" shape with straight side walls. Their purpose is to provide wider horizontal coverage and their straight side walls generate a uniform dispersion pattern in that dimension, but with narrowing directivity in the vertical plane. Bi-Radial® is a registered trademark of JBL and it is similar, but has a more complex flare shape. The popular 2370 acts very much like a radial horn, having greater horizontal dispersion and narrowing directivity in the vertical plane. Below 1.6kHz, its vertical directivity begins to widen rapidly because of mouth diffraction, and JBL recommends vertical arrays to lower the frequency where vertical dispersion control is maintained. This is true, of course, for all mixed-dispersion horn shapes. For more information, see JBL's 2370 product literature. As for the crossover, both JBL's Bi-Radial® and their older radial horns work very well with top octave compensation such as is used in the π® Crossover, as do most other CD horns. This crossover has the additional benefit of damping resonance to prevent peaking near the crossover frequency.
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Re: Radial horns [message #40381 is a reply to message #40380] |
Sun, 23 February 2003 00:43 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Alex
Messages: 11 Registered: May 2009
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Chancellor |
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Hey Wayne. Thanks for the info. I read in the JBL documentation file as well that these horns should be stacked on top of each other. Should they be turned upright though? Or just leave them the same position as normal but have more of them on top of each other. I dont understand how this can lower the freq where vertical dispersion is controlled, I would think it just gives wider vertical dispersion?I think it was you before in another post mentioned something that 2" compression drivers should be used to do up to 20KHz. Is this true? I would like to go for a 2", but if 1" is better.... Oh yea, would you reccomend ANY radial horn? (assuming its the right size) or is JBL for example a lot better than others? (I'm thinking of some P Audio horns, but they dont state weather they are radial, conical etc. How can you tell if a horn is a radial one?). Have you used or heard wood horns before? If so, what do ya think of them? Do they sound "nicer", or in particular, have less of a ringing, horn sound to them? If I do decide to build a horn myself, where can I buy the flange that the horn mounts to? (one that takes bolts, not screw on driver). Cant find them anywhere! Thanks again for any help! Alex :)
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Re: Radial horns [message #40384 is a reply to message #40383] |
Sun, 23 February 2003 03:18 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Adrian Mack
Messages: 568 Registered: May 2009
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Illuminati (1st Degree) |
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Hey Wayne. Since a dual throat adapter will need to be used if stacking, the one compression driver will be used for two horns (I think). I've heard that this can increase distortion? On radial horns where the horizontal and vertical dispersion pattern is the same (like 60 x 60 degrees etc) are these suitable for the compensation circuit of yours? As radial horns dont add any garbage to the response (or something!) so your circuit will work good with them, I am wondering if a horn like this will suit it as well (its still radial). That way I wouldn't need to stack them, or spend money on extra horns and a dual throat adapter. But I've also seen that 90 x 40 degree are the best dispersion pattern. Just another note on the 2" compression driver, the response curve shows the high end response to be similar to comparable 1" compression drivers I've seen, with the compensation circuit making even better (like duh!). This is all on paper though, I dont have any experience with sorts of drivers, I actually want them to cover 500Hz to 20KHz (the JBL 2370 is 630Hz lowest I think which is close enough :) I've found graphs of 1" compression drivers that shows it going flat down to 500Hz, but the manufacture still states a resopnse from like 1.5K to 20KHz! Why's this? I'm thinking it might be best to go with a 2" driver, but I'd like to hear what you have to say on this! For the graph example this page here http://www.paudio-europe.com/products/db_product.htm?v_tipo=2&v_tipo_desc=DRIVERS&v_num_series=6&v_des_series=BM-SERIES&v_id_art=42 As you can see the specs say 1.5KHz-18KHz but the graph shows it going to 500Hz! Thanks! Adrian
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Re: Radial horns [message #40388 is a reply to message #40383] |
Sun, 23 February 2003 14:23 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Adrian Mack
Messages: 568 Registered: May 2009
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Illuminati (1st Degree) |
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Hey Wayne, thanks for your help so far, just have a couple of last questions.I'm thinking that the 1" compression driver may indeed be the way to go so I dont loose out on HF performance. But the reason I wanted the horn to go to ~500Hz and up is that the vocals are supposed to sound a lot better when coming from the one speaker. I know there are vocals below 500Hz but this is meant to be the best way to do reproduce them. Also, I didn't want half the vocals coming from a direct radiator (like a 12" or 15" to cover down to 70Hz or so with the horn) and the other coming from a wide dispersion horn, might make it sound a bit funny off-axis? Have you got any comments on this matter? Cheers! Adrian
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