| Push-Pull horns [message #20314] |
Fri, 27 August 2004 07:30  |
martin seddon
Messages: 2
Registered: May 2009
|
Esquire |
|
|
|
Hi, I recently built what I call a push-pull horn and would like to chip in with my own experiences. It started out with a large fibre glass 160Hz front horn for a Lowther PM2a. Then I made an L shaped 2.2m 7000cm2 f/glass and ply horn for bass using a CA25FEY. I had cross over difficulties I didnt know how to solve and eventually adapted the horn to back load the Lowther. This was done by breaking the top round fibreglass section over to mate with the mounting plate on the fronthorn. So there are only 2 x 90 degree bends (using reflector plates. The driver sits in the throat of the backhorn - with no throat chamber. HornResponse predicted it would work down to 50Hz at c. 102 dB - and I think it may actually be true in practice - tho I havnt measured. It works much better than I expected - great bass integration. A
|
|
|
|
| Re: Push-Pull horns [message #20315 is a reply to message #20314] |
Fri, 27 August 2004 10:42  |
GM
Messages: 114
Registered: May 2009
|
Viscount |
|
|
>Extended HF down the back horn is OK.
====
If the 'XO' point is kept low enough, I agree, but I've experimented enough with BLs that above ~250Hz (some say as low as 100Hz) I find the comb filtering unacceptable, so as always YMMV.
====
>The back horn throat chamber (LP acoustic filter)is best eliminated - this removes the nasty looking peaks (phase inversions?) shown by HornResponse - which even if well down, must surely be heard full level from the front.
====
Hmm, if you design the horn properly, the filter doesn't cause this due to the first section of the horn damping it. I assume that either by design/experimentation/blind luck yours works due to having the ~correct first section that is in effect the LP filter.GM
|
|
|
|
| Re: Push-Pull horns [message #20316 is a reply to message #20315] |
Sat, 28 August 2004 07:11 |
martin seddon
Messages: 2
Registered: May 2009
|
Esquire |
|
|
|
Well with my old cloth ears and lack of measuring skills I won't make any rash claims. I build the contraptions as an experiment not expecting that much out of it - and was pleasantly surprised. I think possibly back horns get a bad name (and I've heard a few) because they are not even close to a proper expansion. Once one builds something like the real 50Hz thing (never minding the power to weight ratio, waf etc)one discovers what these drivers can do in the bass end. amazed just how enjoyable and free a single triode / horn can be. best rgds, martin s
|
|
|
|
| Re: Push-Pull horns [message #20317 is a reply to message #20316] |
Sat, 28 August 2004 16:55 |
GM
Messages: 114
Registered: May 2009
|
Viscount |
|
|
|
Agreed, I've yet to hear a 'fullrange' single driver backhorn that has the proper loading for the app other than my few 'proof of concept' designs. GM
|
|
|
|
|
|
|
|
| Re: Push-Pull horns [message #20320 is a reply to message #20319] |
Sat, 28 August 2004 21:19 |
GM
Messages: 114
Registered: May 2009
|
Viscount |
|
|
|
Yeah, when I add enough series R to get the mass corner down to ~250Hz, I calc the flare = ~6Hz, M = 0.509, so for all intent it's a very narrow angle conical horn. GM
|
|
|
|
| Re: Push-Pull horns [message #20321 is a reply to message #20320] |
Sat, 28 August 2004 22:32 |
roncla
Messages: 125
Registered: May 2009
|
Master |
|
|
|
so for all intent it's a very narrow angle conical horn. If real estate is location, location, location then horns are size,size,size.
ron
|
|
|
|
|
|
|
|
Posting Rules
Members
Search
Help
Register
Login
Get a T-Shirt!
