mustang guy Posted January 21, 2014 Share Posted January 21, 2014 I have been reading the BFM forums, and ran across a thread "Why Bill doesn't design tapped horn?". I learned a few things I did not know in reading this thread. I payed particular attention to what Bill had to say. This is a recommended read. Quote Link to comment Share on other sites More sharing options...
jason str Posted January 21, 2014 Share Posted January 21, 2014 Lots of great information on Bill's websight. I would not have gone in business building his cabinets if i did not believe they were the best designs out there for any price. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 21, 2014 Share Posted January 21, 2014 I've read that thread before. It's a shame someone like Tom D couldn't comment as well. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted January 21, 2014 Author Share Posted January 21, 2014 I've read that thread before. It's a shame someone like Tom D couldn't comment as well. He mentions Danley in this thread, and in a positive way. An interesting experiment he gave to people who want to see the distortion in action is here: Bill Fitzmaurice: "Play a 60hz sinewave through the sub, low passed at the subwoofer passband, nominally 100Hz. Content above 100Hz is harmonics. The louder you play the higher the harmonic content will be. Keep in mind the slope of the LP filter. One advantage to a folded horn is that it is itself a low pass filter, its slope cascading with the slope of the electronic filter." That harmonic is distortion would infect an original recording. I don't own a tapped horn sub, so I can't try it for myself. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 21, 2014 Share Posted January 21, 2014 So how do you hear the harmonics over the 60 Hz tone that's being played? Quote Link to comment Share on other sites More sharing options...
mustang guy Posted January 21, 2014 Author Share Posted January 21, 2014 So how do you hear the harmonics over the 60 Hz tone that's being played? I'm not sure I understand the question. If you can see it on an RTA, then wouldn't you be able to hear it too? What I don't know is how loud those harmonics are as compared to the tone being generated. I suppose that is an important fact. Just how much perceivable distortion is there in a tapped horn? Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 21, 2014 Share Posted January 21, 2014 So how do you hear the harmonics over the 60 Hz tone that's being played? I'm not sure I understand the question. If you can see it on an RTA, then wouldn't you be able to hear it too? What I don't know is how loud those harmonics are as compared to the tone being generated. I suppose that is an important fact. Just how much perceivable distortion is there in a tapped horn? I didn't realize he was referring to watching it with an RTA. I thought it was a listening experiment. Reading back what you wrote, you said "see" not "hear". I missed that. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted January 22, 2014 Author Share Posted January 22, 2014 So how do you hear the harmonics over the 60 Hz tone that's being played? I'm not sure I understand the question. If you can see it on an RTA, then wouldn't you be able to hear it too? What I don't know is how loud those harmonics are as compared to the tone being generated. I suppose that is an important fact. Just how much perceivable distortion is there in a tapped horn? I didn't realize he was referring to watching it with an RTA. I thought it was a listening experiment. Reading back what you wrote, you said "see" not "hear". I missed that. Sorry, I also paraphrased his comment... Here is the full volley... Dan_Hoppin wrote: I have a 4 cubic foot Eminence 3015LF loaded cabinet that is ported for about 45hz. It is really my bass cabinet, but I have hooked it up as a PA subwoofer and I don't hear any distortion. Bill Fitzmaurice replied: How do you know? Have you done an RTA ? Distortion doesn't mean it sounds like a fuzzbox, it means there are harmonics not present in the original signal. That is what a fuzzbox does as well, just to a higher, and more obvious, degree. Dan_Hoppin wrote: Bill, you mentioned seeing it with an RTA. How would you do that? Play a sine wave and and look for content at each upper octave? I have some hearing lossf, so if I can see it it would be easier to understand. Bill Fitzmaurice replied: Play a 60hz sinewave through the sub, low passed at the subwoofer passband, nominally 100Hz. Content above 100Hz is harmonics. The louder you play the higher the harmonic content will be. Keep in mind the slope of the LP filter. One advantage to a folded horn is that it is itself a low pass filter, its slope cascading with the slope of the electronic filter. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 22, 2014 Share Posted January 22, 2014 Makes sense. Quote Link to comment Share on other sites More sharing options...
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