Hi,
If possible, how would you go about getting 80-5000Hz from a sealed 14L (internal volume) cube, if not, what subset of that FR would be achievable?
According to the sub datasheet (SVS 3000 Micro) they can go as high as 240Hz and perhaps I could possibly cut over to the tweeter (Fountek NeoX 3.0) a bit lower or even higher?
I'm thinking of the new speaker sitting in front of my subs (dual 8" opposing) and a separate ribbon.
I'm going to use an 8-ch DAC and CamillaDSP for the crossover and so only two drivers max in this cabinet.
I don't listen to music particularly loud, 50% volume, room is 5x5m. Current system is around 30w of amplification going into 88dB speakers.
Thanks.
If possible, how would you go about getting 80-5000Hz from a sealed 14L (internal volume) cube, if not, what subset of that FR would be achievable?
According to the sub datasheet (SVS 3000 Micro) they can go as high as 240Hz and perhaps I could possibly cut over to the tweeter (Fountek NeoX 3.0) a bit lower or even higher?
I'm thinking of the new speaker sitting in front of my subs (dual 8" opposing) and a separate ribbon.
I'm going to use an 8-ch DAC and CamillaDSP for the crossover and so only two drivers max in this cabinet.
I don't listen to music particularly loud, 50% volume, room is 5x5m. Current system is around 30w of amplification going into 88dB speakers.
Thanks.
They don't need to be sealed but the rear will be super close to the front of the sub.
I had started down the path of two midwoofers with around 50cm surface area of cone (140-5000Hz, setup "2.5-way") but that was before I had thought hard about placement.
I sit about 4m away from the speakers.
I had started down the path of two midwoofers with around 50cm surface area of cone (140-5000Hz, setup "2.5-way") but that was before I had thought hard about placement.
I sit about 4m away from the speakers.
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I have a few related (probably stupid) questions I cant seem to find answers to online:
Is there a frequency area where bass starts to need to move a lot of air?
Is there some sort of rule as you're going down the bass octaves how much more air needs to move to keep the same SPL?
Can you use surface area of cone and excursion values to get a rough idea of whether the driver can move enough air at a certain bass level in Hz to get a good result for your listening conditions?
These questions are stemming from seeing driver specs like 1.5L sealed F3 is 146Hz for 50cm surface area of cone and 4mm excursion values and wondering roughly what adding a second identical driver with its own amp channel and DSP to boost the bass will end up doing, does it add 6dB, making it twice as loud and meaning it will be good at 146Hz and it can even maybe go a bit lower to say 120-130Hz?
Probably the FR falls off a cliff lower than 146Hz in sealed so just crossover there?
I'm probably missing something fundamental that would help me logically say that two RS125P-8 in a sealed cabinet would be no good for me below a certain Hz, ballpark, like one RS125P-8 would be no good lower than say 250Hz and two RS125P-8 no good below say 150Hz?
I mean I'm pretty sure I could put everything into WinISD all of the time but I'm trying to grasp the "basics".
Is there a frequency area where bass starts to need to move a lot of air?
Is there some sort of rule as you're going down the bass octaves how much more air needs to move to keep the same SPL?
Can you use surface area of cone and excursion values to get a rough idea of whether the driver can move enough air at a certain bass level in Hz to get a good result for your listening conditions?
These questions are stemming from seeing driver specs like 1.5L sealed F3 is 146Hz for 50cm surface area of cone and 4mm excursion values and wondering roughly what adding a second identical driver with its own amp channel and DSP to boost the bass will end up doing, does it add 6dB, making it twice as loud and meaning it will be good at 146Hz and it can even maybe go a bit lower to say 120-130Hz?
Probably the FR falls off a cliff lower than 146Hz in sealed so just crossover there?
I'm probably missing something fundamental that would help me logically say that two RS125P-8 in a sealed cabinet would be no good for me below a certain Hz, ballpark, like one RS125P-8 would be no good lower than say 250Hz and two RS125P-8 no good below say 150Hz?
I mean I'm pretty sure I could put everything into WinISD all of the time but I'm trying to grasp the "basics".
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Each octave you go down requires 4x the volume displacement to maintain the same SPL.
This spreadsheet by Linkwitz will give you a shortcut to dB at 1 meter for whatever Sd and Xmax you want to put in.
https://www.linkwitzlab.com/spl_max1.xls
This spreadsheet by Linkwitz will give you a shortcut to dB at 1 meter for whatever Sd and Xmax you want to put in.
https://www.linkwitzlab.com/spl_max1.xls
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Thanks, cool, so say my "start" freq is 160Hz, an octave lower would be 80Hz and an octave higher would be 320Hz (according to wikipedia it's 315Hz but close enough).
I've heard of 1/3 so going down an octave in thirds:
160
125 - 2x?
100 - 3x?
80 : 4x
Does that mean going from 160Hz to 125Hz needs 2x the volume displacement, so an extra identical driver gives that?
I've heard of 1/3 so going down an octave in thirds:
160
125 - 2x?
100 - 3x?
80 : 4x
Does that mean going from 160Hz to 125Hz needs 2x the volume displacement, so an extra identical driver gives that?
You're in the ballpark. Logarithms make things a little weird. The midpoint between 80 and 160 on a log scale is 113, so that's where you need 2x. (80*160)^0.5
Similarly, for 3x it's 95 Hz.
160 to 125 Hz is about 4 dB of difference for the same displacement. To make up for that, you need about 1.6x volume displacement, so 2x is better by about 2 dB (20*log(displacement 1/displacement 2).
Also, the frequency column in the Linkwitz spreadsheet is just straight number inputs, so those can be easily changed if you want to check specific values. Just watch the graphing, since the chart type is Line, instead of X Y (scatter), so the graph gets a little squirrely if you don't have octave spaced numbers.
Similarly, for 3x it's 95 Hz.
160 to 125 Hz is about 4 dB of difference for the same displacement. To make up for that, you need about 1.6x volume displacement, so 2x is better by about 2 dB (20*log(displacement 1/displacement 2).
Also, the frequency column in the Linkwitz spreadsheet is just straight number inputs, so those can be easily changed if you want to check specific values. Just watch the graphing, since the chart type is Line, instead of X Y (scatter), so the graph gets a little squirrely if you don't have octave spaced numbers.
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Normal sealed box roll-off is 12 dB/octave. Where you are on the roll-off curve and the Qtc can influence this though. Equalization is often used in subwoofers to overcome natural roll-off, but if you take it very far the excursion requirements can get extreme.