12" Backloaded Horn

[jonazmalcom]

Hi everyone I'm kinda new on this forum so I hope I'm doing things right here.

I'm designing a BLH using hornresp for the first time so things are not very clear for me yet. I'm usin a 12" Pioneer Subwoofer (TS-W305C) I know is not a HiFi sub but I have used a very similar model from pioneer (the 10" version) on a 3 way system that I've built 5 years ago with great results, It has great power clarity and amazing frequency response (I crossed it @ 1000Hz).

Anyway I started from a proven design from Paul C for a Eminence 12" driver and since I know that every BLH has to be design for each driver I knew that I was going to have to modify lots of things to make it right, so I took the liberty to modify the cabinet height to 1100mm (the original design is 81.6mm) to fit my listening area and taking this into consideration I started to try to tune it the best I could in horn resp.

All the driver values are correct and I tried to adjust all the horns sections to flatten the frequency response graph the best I could. This is going to be the low end (sub and woofer) for a 3 way active system (3 separate amps controlled by a dbx driverack) and I plan to cross it @ 1000Hz.

The question is.........How does it look ? I'm on the right track or is it better to start from scratch ?

Thanks in advance and hope someone can help me out.

Jonathan.

 

[freddi]

dunno - I'm not good with hornresp and blh - -here's a hornresp flh using some measured specs I found vs your blh input

https://i.imgur.com/maSA04l.jpg

 

[freddi]

also - I think your driver may be suited for MMJ's 6th order "Super Planar" - - check that thread in the Subwoofer section of Diyaudio.

Compound loading 6th order quarterwave "Super Planar" horns and pipes concepts/builds

 

[jonazmalcom]

Freddy thanks for the quick reply and even though we both are not experts on horn resp I can tell thanks to the images you send me I have a big problem with the frequency curve all the way to 1000Hz and a very big difference in electrical Impedance, so may be I'm doing something wrong with the modeling in hornresp.

About the "super planar" design It looks great but I see 2 problems with than design, first I wan to use only one driver per cabinet and the other I specifically need it to be 1100mm of height

 

[methodarn]

Jonathan, to first, you have incorrect chamber dimension, try to improve Atc. And horn at picture have 3 parts, but in your hornresp schematics it have 4 parts.
I will try to help you.
Regards, dk

 

[turk 182]

it could be that your trying to make the horn extend all the way to 1000 hz.
when your looking at the HornResp sim it's only the horn section, which should be tuned/optimized for low frequency performance, and don't forget in a backloaded horn the driver is also acting like a direct radiator at higher frequency.
i do believe there is a way to sum the two to analyze them but i'm no Hornresp expert.

 

[turk 182]

that design is similar to a JBL 4530 bass bin

 

[jonazmalcom]

Methodarn tanks for your comment, you're absolutely right I got mixed up with the calculations and used 4 parts instead of just 3 like the design, about the chamber dimension how can you tell that is not correct ? as soon as I get home from work I'll try to optimize ATC.

 

[methodarn]

So I did it from scratch, you just need correct sizes a bit

Hope it helps
Regards, dk

 

[jonazmalcom]

Turk, that's where I think I'm a bit confused, I want the horn to cut at a point between 300 to 500Hz I'm going to pair it to with a 5" midbass so may be I can cross it around 400Hz, and if I adjust ATC may be that will solve the problem; the thing that I know for sure s that hornresp is a very powerful design tool but also a very complex one.

Thanks for all your input.

 

[jonazmalcom]

Thank you so much Methodarn did you took in consideration all the driver parameters ? In your experience this design will work (well at least in theory) ?

Thanks again for all the trouble.

 

[jonazmalcom]

Methodarn I downloaded hornresp here at work and now I see what you have done and specially what you were saying about the chamber, now it looks much better on all the parameters.

Finally another question about hornresp, now that you have a working design what is the easiest way to convert that into a drawing ? is there a quick way or you have to manually find put distances and angles ?

Thanks so much

 

[freddi]

thanks too methodarn - your blh happens to look good with the Dayton Pa310-8 https://i.imgur.com/1K7LH4a.jpg