andrewrx7 Posted March 11, 2014 Share Posted March 11, 2014 Can a cab that has had the depth reduced by say 25% sound as good as the cab that is full depth? Or do manufacturers "re-tune" the performance of the cab to sound the same? Just wondering whether there are some physics that means that the slimmer version simply will never sound the same? Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted March 11, 2014 Share Posted March 11, 2014 The depth per se doesn't make much of a difference, but the volume of the enclosure determines how the speaker will perform. Too small and the low end will be choked off while the midbass will be boomy. Quote Link to comment Share on other sites More sharing options...
JPJ Posted March 11, 2014 Share Posted March 11, 2014 [quote name='Bill Fitzmaurice' timestamp='1394571051' post='2392944'] The depth per se doesn't make much of a difference, but the volume of the enclosure determines how the speaker will perform. Too small and the low end will be choked off while the midbass will be boomy. [/quote] Interesting to read that Bill because my perception is that deeper cabs seem to project better - but that's probably just that the deeper cabs are nearer to optimum volume? Quote Link to comment Share on other sites More sharing options...
chrismuzz Posted March 11, 2014 Share Posted March 11, 2014 The markbass 104HF is a huge 4x10 and the low end on it is ridiculous! Quote Link to comment Share on other sites More sharing options...
6v6 Posted March 12, 2014 Share Posted March 12, 2014 (edited) [quote name='Bill Fitzmaurice' timestamp='1394571051' post='2392944'] The depth per se doesn't make much of a difference, but the volume of the enclosure determines how the speaker will perform. Too small and the low end will be choked off while the midbass will be boomy. [/quote] Interesting! I was under the (evidently misguided?) impression that for bass cabs you had to avoid them being too shallow, so as to avoid reflections from the back of the cab interfering with the response of the driver? I have an open back 4x10 guitar cab which is only about 9inches deep, could I seal the back of it and put a new baffle in it with, say, a 15" driver? Until now I had assumed this wouldn't work. Edit: Yes I know I'd need to model the cab wrt volume and the driver specs.. Edited March 12, 2014 by 6v6 Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted March 12, 2014 Share Posted March 12, 2014 [quote name='6v6' timestamp='1394617815' post='2393287'] Interesting! I was under the (evidently misguided?) impression that for bass cabs you had to avoid them being too shallow, so as to avoid reflections from the back of the cab interfering with the response of the driver?[/quote]Reflections from the back of the cab are controlled by lining the cab with damping. Or they're supposed to be, some manufacturers have been known to leave it out as a cost cutting measure. [quote]I have an open back 4x10 guitar cab which is only about 9inches deep, could I seal the back of it and put a new baffle in it with, say, a 15" driver? Edit: Yes I know I'd need to model the cab wrt volume and the driver specs.. [/quote]You could. The Eminence Beta 15 specs well for a sealed cab, it's similar to those used by Ampeg. Quote Link to comment Share on other sites More sharing options...
andrewrx7 Posted March 12, 2014 Author Share Posted March 12, 2014 I tried a closed back 2x10 last night. To my ears, sounded pretty good actually. Compared it to a different manufacturers 2x10 with twin ports on the back, and the close back cab was both louder and, to my ears, had a more rounded sound. Does porting actually do much, or is it 90% hype? Does it matter if the ports are forward or rear facing? Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted March 12, 2014 Share Posted March 12, 2014 [quote name='andrewrx7' timestamp='1394629644' post='2393461'] Does porting actually do much, or is it 90% hype?[/quote]A ported cab can deliver on average 6dB more output in the lows than sealed.That's the equivalent of doubling the cab count or quadrupling the power. But that's only in the lows, and it assumes a properly configured ported cab. There's no difference above roughly 80Hz. [quote]Does it matter if the ports are forward or rear facing? [/quote]No. Port output is omnidirectional. Quote Link to comment Share on other sites More sharing options...
charic Posted March 12, 2014 Share Posted March 12, 2014 [quote name='Bill Fitzmaurice' timestamp='1394631729' post='2393499'] Port output is omnidirectional. [/quote] I thought that if a cab was rear ported and near a wall it was different? I'm probably wrong though Quote Link to comment Share on other sites More sharing options...
chrismuzz Posted March 12, 2014 Share Posted March 12, 2014 I always thought front ports had more "throw" but I'm hardly technical minded Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted March 12, 2014 Share Posted March 12, 2014 [quote name='charic' timestamp='1394632727' post='2393525'] I thought that if a cab was rear ported and near a wall it was different? I'm probably wrong though [/quote]Only if it's within an inch or two of the wall. [quote]I always thought front ports had more "throw" but I'm hardly technical minded [/quote]Look up the definition of 'omnidirectional'. Not only is port output omnidirectional, so is that from the cones up to about 200Hz. Quote Link to comment Share on other sites More sharing options...
charic Posted March 12, 2014 Share Posted March 12, 2014 [quote name='Bill Fitzmaurice' timestamp='1394636994' post='2393578'] Only if it's within an inch or two of the wall. [/quote] Ah fair enough, I thought it was a bit further than that but it's still a reason to be a tad wary if it's a practice combo or the like (where it'll permanently be against a wall in the practice room etc) Quote Link to comment Share on other sites More sharing options...
chrismuzz Posted March 12, 2014 Share Posted March 12, 2014 [quote name='Bill Fitzmaurice' timestamp='1394636994' post='2393578'] Look up the definition of 'omnidirectional'. Not only is port output omnidirectional, so is that from the cones up to about 200Hz. [/quote] I assumed everything was directional, and rear ports worked on reflections and if the cab was touching the floor or not. Good to know! Quote Link to comment Share on other sites More sharing options...
andrewrx7 Posted March 12, 2014 Author Share Posted March 12, 2014 On a cab that quotes a frequency response from 60Hz, presumably porting would not offer much of an advantage then, assuming there is little effect from the ports from 80Hz upwards (Bill's post #8)? As ever, interesting reading, and thanks to Bill for sharing his knowledge. Does he ever sleep?? Quote Link to comment Share on other sites More sharing options...
JPJ Posted March 12, 2014 Share Posted March 12, 2014 [quote name='andrewrx7' timestamp='1394640986' post='2393619'] As ever, interesting reading, and thanks to Bill for sharing his knowledge. Does he ever sleep?? [/quote] Some say he's a ninja and that he has no need for sleep....... Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted March 12, 2014 Share Posted March 12, 2014 (edited) [quote name='andrewrx7' timestamp='1394640986' post='2393619'] On a cab that quotes a frequency response from 60Hz, presumably porting would not offer much of an advantage then, assuming there is little effect from the ports from 80Hz upwards (Bill's post #8)? As ever, interesting reading, and thanks to Bill for sharing his knowledge. Does he ever sleep?? [/quote]Most ported cabs are tuned to 45-50Hz, and the bulk of their output there is from the port. Another factor is cone excursion, which is at a minimum at the tuning frequency. That means a ported cab has even more of an advantage over sealed in the low end in terms of maximum output, as the sealed will reach its excursion limits far sooner. The difference can be 10dB, which is the equavalent of 1000 watts versus 100 watts. [quote]Does he ever sleep??[/quote]I'm five hours behind you. Besides, I cruise the web just as most of you do, while at work. For me work is at my computer in my livingroom, and I don't have to worry about the boss peeking over my shoulder to see what I'm up to. Edited March 12, 2014 by Bill Fitzmaurice Quote Link to comment Share on other sites More sharing options...
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