Hi folks, first time posting. I have long studied the serious bass research that goes on here. I got started wanting to build some BFM T60s, of course, years ago and have also become enamored with the eloquent TH designs that have evolved over here - and yet, I still have not done...anything.
Recently at an outdoor event on a beach I was dismayed by the sound. Long story short, I'd like to build some decent subs that have BIG wheels on them to be lugged on a sandy downhill path 1 mile to the beach. I know that I want BR boxes because I have hand tool only woodworking skills (and patience!)
8 cubic ft (240l) boxes are fine and I'd like to hit 40Hz.
My question is in regards to modeling BR boxes. I have been using WinISD .50a7 and have found that my designs always reach xmax well before approaching the thermal limits. In the graphs below you will see a graph of each box SPL @ 1 meter given the maximum amount of power to hit xmax (each noted in the key). Are BR boxes known to experience over excursion above the port tuning frequency - as you will see from the 2nd graph, showing cone excursion, it is the 50-60Hz range that is causing problems. Then again, maybe all of my modeling is wrong! The cheapo MCM drivers did not list BL - I entered it as "10" but have thought about calculating it and/or moving on to HornResp.
Thanks,
J.P.
PS: 110dB/1m sounds fine to me...it's only for about 20-50 people.
Recently at an outdoor event on a beach I was dismayed by the sound. Long story short, I'd like to build some decent subs that have BIG wheels on them to be lugged on a sandy downhill path 1 mile to the beach. I know that I want BR boxes because I have hand tool only woodworking skills (and patience!)
8 cubic ft (240l) boxes are fine and I'd like to hit 40Hz.
My question is in regards to modeling BR boxes. I have been using WinISD .50a7 and have found that my designs always reach xmax well before approaching the thermal limits. In the graphs below you will see a graph of each box SPL @ 1 meter given the maximum amount of power to hit xmax (each noted in the key). Are BR boxes known to experience over excursion above the port tuning frequency - as you will see from the 2nd graph, showing cone excursion, it is the 50-60Hz range that is causing problems. Then again, maybe all of my modeling is wrong! The cheapo MCM drivers did not list BL - I entered it as "10" but have thought about calculating it and/or moving on to HornResp.
Thanks,
J.P.
PS: 110dB/1m sounds fine to me...it's only for about 20-50 people.
An externally hosted image should be here but it was not working when we last tested it.
I just modeled a single PA460-8 in the 8cuft box tuned to 40Hz and it does not reach xmax until 300W (it's 500W RMS) which is much better. This means that it can reach a solid 120dB 1m at 40Hz and peaks at 122dB at 50Hz. Thanks, that's just the sorta lead I needed.
Modeling the suggested sizes, 4cuft and 53Hz, shows that it does not reach xmax until 500W but lacks extension.
Modeling the suggested sizes, 4cuft and 53Hz, shows that it does not reach xmax until 500W but lacks extension.
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