A some horn questions

1. As I understand it the horn mouth, taper and length are all tuning parameters which are independant of the driver parameters (except diameter). That is to say you would select these parameters due to the response that you want (tuning the horn) regardless of the particular driver to be used.

Therefor the design parameters that are dependant on the T-S parameters are things like front and back chamber volume as well as horn throat. Is this correct?

What would be the effect of using sub optimal drivers (e.g. one with too high of Q)? Would it be detrimental to the driver or just make the resonse less than desireable?

2. I am starting to plan my super horn setup in ernest. I plan on building into a wall that is common with the attached 2 stall garage. For the subwoofer horn I have room for a horn mouth of about 16 square feet and can easily accomodate a horn length of 30 feet (one fold) or more if needed. It is most convenient for me to have the sub horn mouth at the top left corner of the wall but if it is necessary it could come out on the bottom left corner. The midbass, midrange, and tweeter horns would go below or above it respectively. Is there a strong preference for one location over the other?

3. I have tried to use the HornResp calculator but I find the sparse instructions inadequate for my level of understanding (esp. of terminology). Are there any tutorials on that program out there that could provide some handholding?:xeye:

mike
 
In theory, mouth size would only depend on the low cutoff you wanted and the solid angle you were loading the horn into (1/2 space, 1/4 space, etc.). In typical reality, mouth size along with the taper or flair type and the length all work together with the driver and front and rear chamber to determine your final results. Simplified theory usually only applies when you make the horn large relative to the wavelengths you're going to be reproducing, and that's hard to do at low frequencies. This is where hornresp comes in handy - you can use idealized math like Leach's to arrive at a starting point and then tweak in hornresp where you can model a finite horn (Leach and most other simplifications assume a mouth size that approaches infinite) and see the actual response. To expand on this, hornresp is not really a design program. It's more of a final check / tweaking in software instead of building multiple iterations of a horn sort of thing. I suppose you could blindly fumble around in it for a while and eventually end up with something good, but it's not a straight forward process.

Some more advice - if you are going to cut big holes in your wall, don't even contemplate using sub-optimal drivers. The entire project should be designed as an optimized system. Now I'm not saying you shouldn't experiment - I've used the drivers I had around at the time to play with horns and learned a lot of stuff. But I would not start out with cheesy drivers and cut holes in your wall for them unless you just like knocking holes in the walls. ;>
 
Some more advice - if you are going to cut big holes in your wall, don't even contemplate using sub-optimal drivers. The entire project should be designed as an optimized system. Now I'm not saying you shouldn't experiment - I've used the drivers I had around at the time to play with horns and learned a lot of stuff. But I would not start out with cheesy drivers and cut holes in your wall for them unless you just like knocking holes in the walls. ;>

Thanks for the information. When it comes time to actually cut up the house I plan to spring for some proper drivers. I just wondered what to expect when playing with stuff on hand in the learning mode and what parts of the design would be driver dependent. It would be nice if one could experiment with different drivers without major changes to the horn itself in case one wanted to try a hot new driver later on.

mike