I like sealed subs, but most don't go low, but i like to have it low. So i tought maybe i need to try to build one. I would like to hit the 30hz sealed, for hifi applications with an speaker efficiency of 89dB in a sealed config without dsp (sorry, but i hate dsp, it takes away to much of the good sound). Max volume needed is 102dB, so it can be low power, but high power is also good. I would cross it over rather low (100-200Hz) to my tops with a passive crossover. I'll probally drive it with a tube or class AB ss amp (i don't like class D).
It mainly come to find the right driver i think for this, but i did not find it yet. Size of the speaker is less important for me, so the box can be big or small, size of the driver idem.
Can you suggest me drivers that could fit this project. I think i need a low EBP (<50) and fs, and a QTS between 0.4 and 0.7 to do this (but i could be wrong).
And please don't try to send me in an other (ported, horn, TH, TL) direction. I know the advantages of those, but that is not the goal of this project. If it's not possible you think, give me the reasons why (so i can learn).
Thanks in advance.
It mainly come to find the right driver i think for this, but i did not find it yet. Size of the speaker is less important for me, so the box can be big or small, size of the driver idem.
Can you suggest me drivers that could fit this project. I think i need a low EBP (<50) and fs, and a QTS between 0.4 and 0.7 to do this (but i could be wrong).
And please don't try to send me in an other (ported, horn, TH, TL) direction. I know the advantages of those, but that is not the goal of this project. If it's not possible you think, give me the reasons why (so i can learn).
Thanks in advance.
you have basically excluded all practical solutions. An efficient driver will require equalisation (DSP) and power at low frequencies as it has a high fs and low Qts (light moving mass powerfull motor). So what you could try is adding extra mass to an existing drivers cone to make an inefficient driver with a low fs, then put it in a big box. Some car audio drivers may already exist that have very heavy moving mass and therefore may be a place to look. There is a reason the driver you want doesn't exist.
Comparing from measurements and not spec at 102 db
a typical (good) pro example : B&C SPEAKERS 15BG100 (Sub-woofer 15", 8 Ohm, 2000 Wmax)
Home subs :
DAYTON AUDIO RSS390HF-4 (Sub-woofer 15", 4 Ohm, 1000 Wmax)
DAYTON AUDIO RSS315HFA-8 (Sub-woofer 12", 8 Ohm, 800 Wmax)
=> rss390hf-4
a typical (good) pro example : B&C SPEAKERS 15BG100 (Sub-woofer 15", 8 Ohm, 2000 Wmax)
Home subs :
DAYTON AUDIO RSS390HF-4 (Sub-woofer 15", 4 Ohm, 1000 Wmax)
DAYTON AUDIO RSS315HFA-8 (Sub-woofer 12", 8 Ohm, 800 Wmax)
=> rss390hf-4
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So you specify the following properties / constraints:
I have marked the performance specifications in green. The red ones are not specifications, they are one step further in the process: they are the outcome of a system design process. In other words: it is not what you want, is is what you think is a means to get there.
You could state your wishes in specifications that are related to performance and can be quantified. For example, 'passive crossover' could mean that the costs should be below $x or that a sub + top can be connected with one cable (I don't know what you had in mind
). These specifications are set only by you. After these are set, you can take the list to us and together we can think about what box type and driver etc. work best for this situation.
I have marked the performance specifications in green. The red ones are not specifications, they are one step further in the process: they are the outcome of a system design process. In other words: it is not what you want, is is what you think is a means to get there.
You could state your wishes in specifications that are related to performance and can be quantified. For example, 'passive crossover' could mean that the costs should be below $x or that a sub + top can be connected with one cable (I don't know what you had in mind
). These specifications are set only by you. After these are set, you can take the list to us and together we can think about what box type and driver etc. work best for this situation.
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So you specify the following properties / constraints:
I have marked the performance specifications in green. The red ones are not specifications, they are one step further in the process: they are the outcome of a system design process. In other words: it is not what you want, is is what you think is a means to get there. Presumably the red ones can be restated in multiple green ones.
You could state your wishes in specifications that are related to performance and can be quantified. These specifications are set only by you. For example, 'passive crossover' could mean that the costs should be below $x or that a sub + top can be connected with one cable (I don't know what you had in mind
You got it wrong. That it has to be sealed and 30hz is mandatory. Otherwise this project is useless as i already have other subs that go lower. It’s specific a low going sealed sub i want.
If you are using a separate amplifier to power the sub then an analog active crossover with a linkwitz transform would be the obvious non DSP solution. You could even include a parametric EQ for the sub to help tune it to the room. Have a look at Elliot sound products website for some starter ideas.
Edit: If you really want to go passive xo / no EQ then 4th order bandpass would be a good choice. Kind of sealed
Edit: If you really want to go passive xo / no EQ then 4th order bandpass would be a good choice. Kind of sealed
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that one models right, but 1kW for home use is maybe a bit to much. Wich makes me wonder if it would work on lower wattage (like a 100W class AB amp). The case also will have to be big (+/- 300L) to do that, and need a lot of bracing to be stiff enough.
But thanks anyway, it gives me id's...
I'm currently using 2 of these in twin 9 cu ft sealed enclosures. Larger would be even better as they are intended for IB, and the efficiency is around 86dB/1w/1m, but they dig crazy deep as is with an F3 well below the 30Hz target.
22" MTX Audio T9922-22 Jackhammer : 389.573
Meets all the OP's criteria and much more in 324 L/0.5 Qtc or 87 L/0.707 Qtc @ 20 W, so will probably never even be broke in based on its power ratings, but this much performance doesn't come cheap; on sale for $9500 + delivery [I presume].
GM
that is indeed the speaker driver i'm after.
A first modelling with the 8R version goes full flat in a 1250L case (wich is too big), but reasonable (<3dB difference) flat and well below 30hz in a 250L case (wich is a bit big but doable), only the efficiency is a bit low.
But with an active cr it's solvable, and that was the less important condition in my request. I can live with using a active crossover and seperate amp for this sub to combine them with more efficient tops. Or just use an Lpad in the passive cr.
Thanks for giving me a starting point, now the studywork starts how to do this right.
High puffery from manufacturer ("exaggerated or false praise") but seems good.
Low resonance (16 Hz) but bought by selling soul to the devil (half-pound cone assembly).
I wonder about the power handling spec of "300 watt (cont.)" So can it dissipate the heat that a 250 watt incandescent bulb would produce for an hour or so?
Why is it so hard to make a flexible spider with a low mass cone and get low resonance that way? As the OP is looking for.
B.
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