those things also take much less power to reach higher dB. It seems that it's just a lot easier to get high volume upper mids/treble... that could be some of it too.
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anyone using isobaric cabs?
- Thread starter flameworker
- Start date
More in the midrange, ear damage is most likely where hearing is most sensitive. That's why noise regulations are specified A weighted, which measures midrange. Very low frequencies can damage the eardrums, but sources loud enough to do that are usually explosives, not speakers.
"Noise Induced Hearing Loss" is loud noise that damages hearing.
A very loud noise at one frequency can harm hearing at other frequencies.
Take Light, there is ultraviolet and infrared also, What you can't see may not seem harmful, but it sure can be.
It could be a loud noise outside of what you can hear damages what you can hear.
BTW
Isobaric is a waste of drivers.
A very loud noise at one frequency can harm hearing at other frequencies.
Take Light, there is ultraviolet and infrared also, What you can't see may not seem harmful, but it sure can be.
It could be a loud noise outside of what you can hear damages what you can hear.
BTW
Isobaric is a waste of drivers.
Any frequency can damage hearing given enough SPL over a given period of time. With the type of bands I play with, it's cymbals and distorted electric guitar. I do wear hearing protection.
- Nov 24, 2008
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I think hearing loss at high frequencies is more common (and more obvious), but the problem with low-frequency energy at high volume is, ear protection is a lot less effective because the energy transmits right through your skull bones. So there really is no way to protect against it. Low-frequency hearing loss was very common among Viet Nam era helicopter pilots, for example.
You can use different models, but it takes a bit of juggling. I've done it, and sorry but the details are something I'm keeping under my hat for now.
Several years ago I experimented fairly extensively with isobaric loading for home audio applications. I found that isobarics do some things very well and some things very poorly. There may be a window of opportunity for an isobaric bass cab, and I may give it a shot one of these days, but it would be a rather specialized cab.
The current theory predicts that all you get from isobaric loading is a halving of the required box volume. My observations were not matching up well with that, so out of curiosity I built two test boxes, a two cubic foot sealed box and a one cubic foot sealed isobaric. They should have had identical low-end response. But the isobaric box behaved as if the Qtc was significantly higher. I did not measure the efficiency, as that wasn't of interest to me at the time. Anyway in retrospect I believe that the air mass in the "iso-chamber" couples to the cones and increases the effective moving mass, raising the system Q, and presumably lowering system efficiency accordingly as well.
I'm going to test it with the cheapest 8"drivers I can find.
It might work to make an excellent practice amp.
Imo, it Requirestoo much wattage, and wastes an expensive driver for real use, but if you were using something like a $20, 50 watt mcm driver, maybe that is where isobaric can shine.
It might work to make an excellent practice amp.
Imo, it Requirestoo much wattage, and wastes an expensive driver for real use, but if you were using something like a $20, 50 watt mcm driver, maybe that is where isobaric can shine.
The markbass 210 and 115 is what I was using to compare. I wish the drivers they were using were more affordable, they have B&C NEO s in them, my current favorite speaker is the 500w 15, it's incredibly full range, and feather light. But $$$.
Oh, i have these little 5" 100 watt ross*(kustom) drivers that will be perfect to test, nice and little so moving/sliding things around will be easier.
They take wattage great, but all mid range.
I have been using these for a bunch of experiment s.
They take wattage great, but all mid range.
I have been using these for a bunch of experiment s.
If you greatly increase the coupling volume and you use drivers with a low Mms you should take the air mass into account, this is a known fact for Isobaric(compound) enclosures. Btw. this will also make the coupling between the two drivers "softer".
There are a lot of parameters one can fiddle with to achieve different results and increasing the coupling volume is one of them. You could also e.g. use a different driver on the inside but results will not be very predictable, experimenting is the key here (visaton Atlas MKIII Invalid Link Removed )
And of course one can use Isobaric in conjunction with bassreflex, 4th and 6th order bandpass, TL's and so one... I've did a lot of experiments in the past with this type of stuff but IMO it's main use would be HT/home-hifi subwoofers and not basscabs.
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Genz Benz had a budget range called the focus LT. I think they've been discontinued since. Well anyway I bought the 1*15 and 2*10 cabs for the price of an Orange SP212. They're light enough (ceramic drivers) and they sound fantastic for the price. Really good quality cabs made in the US. OK they're rated at 300W not 500w but they're so light you can stack the 2 easily without breaking your back. Or get the 4*10. Look out for these, they're great.
Genz Benz had a budget range called the focus LT. I think they've been discontinued since. Well anyway I bought the 1*15 and 2*10 cabs for the price of an Orange SP212. They're light enough (ceramic drivers) and they sound fantastic for the price. Really good quality cabs made in the US. OK they're rated at 300W not 500w but they're so light you can stack the 2 easily without breaking your back. Or get the 4*10. Look out for these, they're great.
May I ask which drivers you used, how big the internal,- and coupling-volume of that test-cabinet were? Because the "theory" predicts halving of the Vas on the facts I mentioned in post #11
Adding additional mass will lower Fs and increase Qms and Qes.
Hiho,I use an Orange sp212 isobaric cab like a lot of us Terror bass users and you don,t hear us complaining about them.
When I tried it out I tried a valve ashdown head and cab,markbass head and cab and the Orange terror bass 500 with a sp212 cab,mixed and matched all the cabs and heads and come away with the Orange rig,just sounded right for me.
18 months later,100 gigs a year,practices and no PA support.It just kicks it,s way through the mix.The only thing that could be an improvement is to add another sp212 cab if they were more affordable and you don,t see many coming up S/H.
When I tried it out I tried a valve ashdown head and cab,markbass head and cab and the Orange terror bass 500 with a sp212 cab,mixed and matched all the cabs and heads and come away with the Orange rig,just sounded right for me.
18 months later,100 gigs a year,practices and no PA support.It just kicks it,s way through the mix.The only thing that could be an improvement is to add another sp212 cab if they were more affordable and you don,t see many coming up S/H.
- Nov 24, 2008
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It was a Dynaudio woofer, and the name "21W54" comes to mind. I don't remember the exact ratios of the internal chamber volumes, but based on what I do remember of the build, I'd estimate about 1/4 to 1/3 of the internal volume was in the "iso-chamber", and the rest in the "inner woofer chamber".
Cool, Dynaudio did build a few Isobaric designs themselves (compound series)
Those 21W54 were(still are) very impressive drivers, their Mms is 27grams.
Lets say that the air mass is 1290gr per m3, then 10liters of air is 12,9grams, so if the coupling volume would be 10liters you'll allready add 12,9grams to the Mms of the "compound"driver.
Isobaric made sense for hi-fi woofers back in the 60s, when giant vas values made it necessary to use giant cabs. Once T/S specs came along speaker designers figured out how to make speakers that didn't need huge cabs and isobaric was made obsolete. This is another one of those speaker engineering facts that you learn when you study the history of speaker design. You seem bound and determined to keep on reinventing the wheel, but no matter how many times you do its always going to end up round.
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In the case of the Focus cabinet line, much of the thrust of the engineering centered around the unavailability of Neo material at a reasonable price so we revisited some if the basic mechanics of driver design looking at weight versus performance tradeoffs without cost being the sole dominating factor (as it had been in the industry for years). Turns out there were several options available to us at a $/oz cost less than the $/oz cost of neo so we were able to settle on a nice middle ground between cost, weight and performance. Simple things like materials capable of higher flux density before saturation resulting in different pole piece geometries and back plate thicknesses, different ferro-ceramic grades, and optimizing the motor loads for the redesigned lighter weight motor.
This is an example of a less expensive product through better engineering rather than making it cheaper. In fact it's a more expensive ceramic driver that has higher performance/weight but at a somewhat greater cost that was still much less than a comparable neo. The weight savings was about I between a conventional ceramic and a neo, but the cost was maybe 25% more than a conventional ceramic and 50% less than neo.
Engineering is the art of managing multiple compromises
This is an example of a less expensive product through better engineering rather than making it cheaper. In fact it's a more expensive ceramic driver that has higher performance/weight but at a somewhat greater cost that was still much less than a comparable neo. The weight savings was about I between a conventional ceramic and a neo, but the cost was maybe 25% more than a conventional ceramic and 50% less than neo.
Engineering is the art of managing multiple compromises
