To get anywhere near your goal out of a 30L box, you'll probably need to replace that vent with a PR. At that point is basically becomes a task of choosing a driver and PR with enough excursion, and an amp powerful enough to get the best out of them.
^ For example: a CSS SDX10 in 30L with two of their APR10 10" passive radiators models at slightly over 114db at 40hz at full power (750w)
D
Deleted member 375592
Before I moved, I used to run Focal 30A4 from a closed box ~40L sitting in the corner (pi/2). How low in frequency you get depends on the room acoustic.
Passive radiators won't work with the form factor I have in mind. But it's an interesting option.
That CSS SDX10 is a nice speaker. But it weighs more than the 12" we were talking about. And I don't have the surface area for passive radiators.
Yes corner loading is a good option, but doesn't work outside.
That CSS SDX10 is a nice speaker. But it weighs more than the 12" we were talking about. And I don't have the surface area for passive radiators.
Yes corner loading is a good option, but doesn't work outside.
InTheWorks, could you share a bit more about your application?
I work with PA systems and live music, and I'm not the only one around here that does. I've designed and built a few PA systems, ranging from fairly run-of-the-mill stuff, through to theatre SFX reaching <20Hz, to some really compact cabinets that do very well for their size.
FWIW, kick drum SPL estimates come in at around 140dB for close-mic'd applications. At a greater distance, 110-120dB@1m would be pretty reasonable. The smallest subwoofer I'd use for reinforcing a live drum kit would be 1x 12" subwoofer, groundplane, with enough power to hit >115dB. Even then, I'd use a compressor (set more like a limiter) on the kick channel, to make sure an extra hard kick* doesn't cause problems.
* I've seen drummers hit 20dB harder between soundcheck and the show.
Chris
The CSS SDX12 will do 106db at 2pi in 32 liters but I don't think sound reinforcement is it's forte. https://www.audioholics.com/subwoofer-reviews/css-sdx12/conclusion
However, I would maybe focus on 60hz up as most bass guitar cab alignments do (looking at Eminence bass guitar speaker alignment recommendations). I think the first harmonic of the low E (82hz) comes through stronger anyway.
However, I would maybe focus on 60hz up as most bass guitar cab alignments do (looking at Eminence bass guitar speaker alignment recommendations). I think the first harmonic of the low E (82hz) comes through stronger anyway.
A 12" x 12" x 12" enclosure could fit a 12" on the front, a pair of passive radiators on the sides, and a top hat pole mount on the top.
What form factor do you have in mind?
The application is pretty basic. I just don't want to drag my acoustic kit out to the back yard. I have a compact electric kit that I play with headphones. I'd like to take the compact kit outdoors instead. One of my kids has a bass guitar and 15" bass cab. My other kid has a guitar and that amp gets ridiculoulsly loud in a small package.
The goal is to take one speaker into the backyard (or maybe a pair for stereo one day) and plug all the instruments in. I also want to use this speaker as a monitor for my electric kit inside.
The commercial offerings leave much to be desired except form factor. The commercial amp that I'm trying to best is the Alesis Strike 12. Here's a link. It makes some ridiculous claims. If I purchased said amp I'd have to put an EQ in front of it. Whereas if I build my own, I can throw an ADAU1701 in it.
In order to have equal loudness, 40Hz is the limiting factor (low E on bass guitar, fundamental of most kick drums). So that's it.
The goal is to take one speaker into the backyard (or maybe a pair for stereo one day) and plug all the instruments in. I also want to use this speaker as a monitor for my electric kit inside.
The commercial offerings leave much to be desired except form factor. The commercial amp that I'm trying to best is the Alesis Strike 12. Here's a link. It makes some ridiculous claims. If I purchased said amp I'd have to put an EQ in front of it. Whereas if I build my own, I can throw an ADAU1701 in it.
In order to have equal loudness, 40Hz is the limiting factor (low E on bass guitar, fundamental of most kick drums). So that's it.
Here's an article I wrote on PA speakers and their specifications: https://www.prosoundweb.com/spec-wars-looking-inside-loudspeaker-spl-specifications/
I also did some tear-it-apart-and-measure-everything testing on a Yamaha DBR10, which was 10dB into excursion limiting (ie, reducing the bass) before the "limit" light engaged with the peak limiter.
As a further datapoint, I had a musician (guitarist) using a similar model to that Alesis (inc power rating, price point etc) on-stage. One of my older-model 350W RMS 12" 2-way monitors demolished it for output and clarity. It wasn't even a close call. In the end, he switched his speaker off and just went with my monitor.
A good 12" 2-way PA speaker will do the job you're looking for, if you can live without the "solid" sound that true 40Hz extension gives you.
If you still want to hit 40Hz, I'd recommend building a 2-way speaker around a 12" PA subwoofer and a reasonably heavy-duty compression driver. It won't get as loud as a more-efficient driver playing 70Hz-and-up, though.
FWIW, if it was mine, I'd aim at 60Hz and call it good. You only miss the extension in direct A/B comparisons.
Chris
I also did some tear-it-apart-and-measure-everything testing on a Yamaha DBR10, which was 10dB into excursion limiting (ie, reducing the bass) before the "limit" light engaged with the peak limiter.
As a further datapoint, I had a musician (guitarist) using a similar model to that Alesis (inc power rating, price point etc) on-stage. One of my older-model 350W RMS 12" 2-way monitors demolished it for output and clarity. It wasn't even a close call. In the end, he switched his speaker off and just went with my monitor.
A good 12" 2-way PA speaker will do the job you're looking for, if you can live without the "solid" sound that true 40Hz extension gives you.
If you still want to hit 40Hz, I'd recommend building a 2-way speaker around a 12" PA subwoofer and a reasonably heavy-duty compression driver. It won't get as loud as a more-efficient driver playing 70Hz-and-up, though.
FWIW, if it was mine, I'd aim at 60Hz and call it good. You only miss the extension in direct A/B comparisons.
Chris
That was a good article.
I find any product that doesn't have a proper set of measurement curves very fishy. You can not describe a speaker by a single number. I think it's too much for the masses to understand though.
What kills me about speakers like the Alesis model is it claims 2000W. Meanwhile the rear plate says 600W. I don't understand how marketing can justify that. It's probably not awful value if you consider never turning it up past vol 5.
The problem with not enough 40Hz is that the kick is quiet and the toms are thunderous. So I wouldn't want to aim for 60Hz. There are definitely tradeoffs.
I find any product that doesn't have a proper set of measurement curves very fishy. You can not describe a speaker by a single number. I think it's too much for the masses to understand though.
What kills me about speakers like the Alesis model is it claims 2000W. Meanwhile the rear plate says 600W. I don't understand how marketing can justify that. It's probably not awful value if you consider never turning it up past vol 5.
The problem with not enough 40Hz is that the kick is quiet and the toms are thunderous. So I wouldn't want to aim for 60Hz. There are definitely tradeoffs.
It's worth noting that the 600w vs 2000w thing is entirely legitimate.
The 600w rating comes from driving the amplifier (apparently capable of 2000w peaks) to the onset of clipping using pink noise with a 9dB crest factor. ie, if the peaks are 2000w, then the average power being delivered is 250w (9dB is a power difference of 8x). Factor in some inefficiencies, and the 600w rating will appear.
FWIW, "vol 5" is pretty meaningless if there's horrendous distortion when you hit "6". The manufacturer is playing a game there - people will assume the volume difference going from "2" to "4" can be maintained up to "10". Few products manage it, but the amateurs are impressed when they notice how loud it is "not even half-way up".
With regards to LF extension, perhaps a different kick drum sound is in order.
Chris
The 600w rating comes from driving the amplifier (apparently capable of 2000w peaks) to the onset of clipping using pink noise with a 9dB crest factor. ie, if the peaks are 2000w, then the average power being delivered is 250w (9dB is a power difference of 8x). Factor in some inefficiencies, and the 600w rating will appear.
FWIW, "vol 5" is pretty meaningless if there's horrendous distortion when you hit "6". The manufacturer is playing a game there - people will assume the volume difference going from "2" to "4" can be maintained up to "10". Few products manage it, but the amateurs are impressed when they notice how loud it is "not even half-way up".
With regards to LF extension, perhaps a different kick drum sound is in order.
Chris
