My EA iP-4 prototype cab has 2X10's w/2X8's mounted behind the 10's. I would think that for continuity sake the individual "pairs" should match.
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anyone using isobaric cabs?
- Thread starter flameworker
- Start date
I wasn't clear. I just mean your standard speaker cabinet with the front of the speaker visible and open to air vs hidden/deep horn mounted speakers.
This
vs this
Ah, two different design goals. Folded horns (horns in general) are more efficient at their limited bandwidth (designs limitations). Bandwidth is not as limited by the bass reflex (driver limitations).
No free lunch.
No free lunch.
I had an isobaric SP212 with the terror bass amp.Thought it was ok...until I used the amp with a conventional 15" Genz benz cab. Not only was there more depth to the sound, there was more clarity in general across the entire spectrum. I finally got the p bass sound I always wanted (I was blaming the bass all along !) I since sold on the Orange 212. Don't really see the point of the isobaric system. A lot of 12x1 cabs can handle up to 400w now anyway (markbass for example) they're lighter and cheaper.
Exactly my point. You can get more sensitivity per watt given the same speaker but as you mention only for specific frequencies and you'd need to add additional cabs for mids/highs and crossovers etc. big heavy and complicated. Those additional DB would be easier to achieve with more power or more speakers or both.
Some of the transmission line woofer designs (as used by PMC and Wisdom Audio** in the studio monitoring and custom home theater markets respectively) achieve the goal of increased output via constructive interference. (Though I don't think it's "doubled" LOL!) Not sure if anyone has ever applied these designs to a commercially-produced bass guitar cabinet.
An old friend of mine (who has a Mechanical Engineering degree with an emphasis in acoustics from MIT) designed a 1x10" transmission line cabinet way back in the late 1970s, and it certainly went lower and played louder than any 1x10" cabinet in the late 1970s did. (of course, there weren't a whole heck of a lot of 1x10" bass cabinets in the late 1970s!) And yes, it was one deep ass cabinet: While the front baffle was barely wider than the 10" driver, it was almost 48" tall and 48" deep...kinda looked like a Marshall 4x12 cabinet turned sideways!
** There's a nice white paper describing Wisdom's Regenerative Transmission Line design here: Invalid Link Removed
- Mar 8, 2011
- 12,232
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- Authorized greenboy designs builder/Owner of BNA Audio
I've heard some great home hi-fi transmission line cabs, but for electric bass they'd be way too big and expensive, sadly.
I don't want to upset anyone so I'll just direct quote from the document and let you make your own conclusions.
"Combined with intelligent subwoofer placement in the room and the room correction that
is included in all Wisdom Audio Sage Series systems (in the SC-1 System Controller)"
Portable bass cab that the average musician might use?
"Combined with intelligent subwoofer placement in the room and the room correction that
is included in all Wisdom Audio Sage Series systems (in the SC-1 System Controller)"
Portable bass cab that the average musician might use?
THIS!!!
I've had to stop myself from tackling an experimental build with this configuration more times than I care to mention. It just seems so very interesting. I wish I could hear a well executed one in person.
I think the question is...do you want low boom or low clarity? I personally don't want to hear much below 60hz....it's just not good for our bodies. I find that on a 4 string, I get more bass in the 80-120 hz range than I do in the sub 80hz range. It's warm and strong in that range. In the 120-500 hz I get definition and in the 500-1.2khz I get the honk and tone I'm after. I'f I'm after a solid low end, it's 80-120 hz which seems to do the trick and it seems easy on my ears too.
I think there's a lot of wisdom in this post. There's low-end and then there's usable low-end. Most bass amps have a ton of low-end on tap, but most of it is not really usable in sort of musical way. Even though it's called a bass guitar, it's really an instrument that gets most of its body from the low-mid area. Even the best bass tone in reggae music has as much emphasis on the low-mids as it does the lows. The lows in bass guitar reproduction should never be overpowering. They should sit as a tight foundation that smoothly transitions to the low-mids. If you start pushing too much low-end, then you end up with that boomy, undefined mess fighting with the kick drum that's indicative of just about every hack sound guy's mix.
IMO, there's simply no reason to use an isobaric design anymore. The Kappalite drivers comming out of Eminence are so well engineered, and cab designers like Greenboy know how to take maximum advantage of them.
One of the first bass guitar cabs I built was an isobaric cab using two Peavey Black Widow 15's (because that's what I could get my hands on) in a push pull configuration. I even went to the trouble to mount them very close, nesteled, facing the same way thinking that would make the coupling tighter. Even with the box volume reduction of the isobaric configuration, it was huge because the Vas of the drivers was enormous and I was probably going for something like an F3 of 30 hz. It worked but it sucked at anything but low volume sub-bass. Higher frequencies interfered with each other between the two cones and of course those drivers didn't have the excursion to do what I wanted them to do - even if I had used them in a 2-way system.
IME people that think going below the 60-80hz range is a bad thing, are playing poorly engineered cabs. That boom/lack of clarity comes from having too much signal below your cabs capabilities.
YMMV.
Well, I have two cabs which I engineered myself using software to plot the response curves and the drives and cross overs were top spec Eminence units. The ports were carefully plotted and the cabinets I built to very good standards. So, while I hear your comments, I disagree with your opinion. Most hearing damage occurs at the low end of the sonic spectrum and it's also where most of an amps power is applied too. So if you want to put 400w at 50hz into your ears while standing only a few feet away from your cabs....good luck with that!
