Effective area is actually larger with 2 pcs in this case. Generally using more smaller speakers can result in a stiffer and more responsive bass than using one bigger with the same cone area.
If the f3b is about the same, I would suggest using 2 speakers. But then you will have to wire them in parallel. Resulting in 4 ohm speakers. And who wants that...
If the f3b is about the same, I would suggest using 2 speakers. But then you will have to wire them in parallel. Resulting in 4 ohm speakers. And who wants that...
Hi,
sub / bass wavelengths are room sized and room dominates the response. Bass response due to room modes typically has 10-20db peaks and valleys. Using two boxes instead of one allows you to effectively increase the size of the source as long as they are spaced apart, opposite sides of room for example, and get some control over the bass response from the room. In other words you would be able to get smoother in room response with two bass boxes instead of one, especially if you have DSP and tune it. You can find more info on this with "multi-sub".
Two drivers could be used in single box as well, in "dual opposing" arrangement which would reduce vibration if that is important feature, but this is still subject to room modes. You could use two woofers on multiple boxes.
Needless to say SPL at these low frequencies is nothing but volume displacement, cone area times excursion.
From these one can now reason: calculate SPL requirement you want to listen to + headroom to get displacement you need. Then if you can split it up to multiple boxes you could get smoother response in room, and/or vibration cancellation. If you have loads of amplifier power you can use smaller boxes. Bigger boxes are needed to get the same volume displacement with small amplifier.
Example:
https://www.diyaudio.com/community/threads/volume-displacement-for-spl-chart.5668/
About 500cm3, half a litre, volume displacement is needed to get about 105db at 30Hz in closed box, simplifying and not considering effects of room or how sensitive hearing is for these frequencies this could be our minimum requirement for bass system. 105db would be 90db listening level with 15db dynamic headroom.
That is roughly two 8", whose Sd is around 230cm2, doing roughly 1cm p-p excursion, which probably means generous distortion on many drivers. Single 10" above could barely make it playing full tilt.
For comparison, single 15" driver has roughly 850cm2 cone area, so about 6mm p-p would be required. Two 15" would make it 3mm p-p excursion, much less amplifier power, less heat, probably less distortion. Lot more headroom at least, for occasional party for example.
You could use four of those 8", or 10", or better yet some 15", and distribute them around the room. Low distortion output at low frequencies and combating room modes is no joke, quite serious "room sized" system is required, especially if one likes to party. Although, daily listening levels are quite modest so even small system have some chance, so anything is fine if it meets the expectations
Have fun!
sub / bass wavelengths are room sized and room dominates the response. Bass response due to room modes typically has 10-20db peaks and valleys. Using two boxes instead of one allows you to effectively increase the size of the source as long as they are spaced apart, opposite sides of room for example, and get some control over the bass response from the room. In other words you would be able to get smoother in room response with two bass boxes instead of one, especially if you have DSP and tune it. You can find more info on this with "multi-sub".
Two drivers could be used in single box as well, in "dual opposing" arrangement which would reduce vibration if that is important feature, but this is still subject to room modes. You could use two woofers on multiple boxes.
Needless to say SPL at these low frequencies is nothing but volume displacement, cone area times excursion.
From these one can now reason: calculate SPL requirement you want to listen to + headroom to get displacement you need. Then if you can split it up to multiple boxes you could get smoother response in room, and/or vibration cancellation. If you have loads of amplifier power you can use smaller boxes. Bigger boxes are needed to get the same volume displacement with small amplifier.
Example:
https://www.diyaudio.com/community/threads/volume-displacement-for-spl-chart.5668/
About 500cm3, half a litre, volume displacement is needed to get about 105db at 30Hz in closed box, simplifying and not considering effects of room or how sensitive hearing is for these frequencies this could be our minimum requirement for bass system. 105db would be 90db listening level with 15db dynamic headroom.
That is roughly two 8", whose Sd is around 230cm2, doing roughly 1cm p-p excursion, which probably means generous distortion on many drivers. Single 10" above could barely make it playing full tilt.
For comparison, single 15" driver has roughly 850cm2 cone area, so about 6mm p-p would be required. Two 15" would make it 3mm p-p excursion, much less amplifier power, less heat, probably less distortion. Lot more headroom at least, for occasional party for example.
You could use four of those 8", or 10", or better yet some 15", and distribute them around the room. Low distortion output at low frequencies and combating room modes is no joke, quite serious "room sized" system is required, especially if one likes to party. Although, daily listening levels are quite modest so even small system have some chance, so anything is fine if it meets the expectations
Have fun!
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Wow, thank you so much for the many and quick responses.
I still have to read into a few things better.
To be a little more specific with my question or to name the application.
I would like to build some kind of Illuminator-4 from Troels Gravesen.
And since I'm more into a slim design I would like to replace the 26W driver with 2 22W drivers. and make the enclosure of the Bass unit a little bit smaller
I know that this is not a simple thing to do and would require a lot of measurements and crossover tuning and also volume changes. I would just like to know if this would tend to be feasible with 2 x 22W.
I still have to read into a few things better.
To be a little more specific with my question or to name the application.
I would like to build some kind of Illuminator-4 from Troels Gravesen.
And since I'm more into a slim design I would like to replace the 26W driver with 2 22W drivers. and make the enclosure of the Bass unit a little bit smaller
I know that this is not a simple thing to do and would require a lot of measurements and crossover tuning and also volume changes. I would just like to know if this would tend to be feasible with 2 x 22W.
There is also a 22W as 4 ohm if I wire them in series I get 8 ohm again would it not be ok to wire in series?
I see what you mean. I'm not necessarily interested in actually putting it into practice, but rather in learning a little more about some things from such mind games.For sure, except you need to measure the speaker and design new crossover if you make these changes
Yes. If there's a 4 ohm version available it is preferred to wire them in series to get a 8 ohm speaker.
Better to make the dual woofers a 1.5 way for baffle step loss, best overall blend to the mids.