Ok, so 1.5m is a close listening distance. Two or 3m would be more typical but then you need to also be able to separate the speakers far enough apart too. I'm not really sure that making it 1.7m is going to offer that much of a significant improvement over 1.5m. Sitting that close to a big speaker means that you're going to be at sharper angles to the lower drivers so the FR might be affected and the sound may not integrate so well as sitting further back. The shorter distance also means that you should make the tweeter height as close as possible to the listening height.
I think it is possible however to reduce the box volume enough to reduce the depth by 15cm or so but that will also raise the tuning from about 27Hz right now to about 33Hz. But we can't do much to move those big drivers closer to each other.
Most music doesn't have a lot of content below 40Hz. That's low E on the bass guitar. Some does however. Output down to 33Hz and then some room and boundary enhancement below that may be fine for your situation. Remember that the closer the drivers are to the back and side walls then the more the low frequencies are reinforced.
Your choice of trade-offs I think.
And then of course, there's which design you think looks better...... 😉
I think it is possible however to reduce the box volume enough to reduce the depth by 15cm or so but that will also raise the tuning from about 27Hz right now to about 33Hz. But we can't do much to move those big drivers closer to each other.
Most music doesn't have a lot of content below 40Hz. That's low E on the bass guitar. Some does however. Output down to 33Hz and then some room and boundary enhancement below that may be fine for your situation. Remember that the closer the drivers are to the back and side walls then the more the low frequencies are reinforced.
Your choice of trade-offs I think.
And then of course, there's which design you think looks better...... 😉
Also, any chance of re-arranging your room so you can sit further away?
Even in a small bedroom I once lived in, I was able to sit farther than 2m by setting my bed up on pivot points like a Murphy bed and swinging it up against the wall. The acoustics even seemed to improve with the large area of foam behind my head.
Even in a small bedroom I once lived in, I was able to sit farther than 2m by setting my bed up on pivot points like a Murphy bed and swinging it up against the wall. The acoustics even seemed to improve with the large area of foam behind my head.
Actual distance of separation between speakers 2,4 meters
I can left only 40cm from rear wall If I do so the new distance between speakers & listening position is 3 meters
Are these room measures OK?
I can left only 40cm from rear wall If I do so the new distance between speakers & listening position is 3 meters
Are these room measures OK?
close to backwall is easier to handle than too short listening distance
main problem is driver summing
very small room can be a problem
many reflections can lead to harsh sound
your need a very well behaved speaker
generally, I would say you might get better sound with 2way + active sub
but a 2way have a certain SPL limit
considering you use your old 2way as part of the new 3way, I would say what changes most is xo point between 2way and the new added woofer
Ok, that's much better.
If the speaker is 58cm deep and you have 40cm space to the back wall, then the front of the speaker is pretty much 1m away from the wall. Seating distance is now 3m which is great. Sounds like you had planned to have the speakers *way* out into the room before. So this is good. It leaves you with some room to play with when you get around to setting them up.
Thanks guys, there is a way much simple than Matrix to bracing the woofer cab?
Something like the this link Cabinet design?
Something like the this link Cabinet design?
Frequently the best way of doing things is also the hardest. Matrix bracing definitely requires more work and material but produces a very non-resonant cabinet.
The cross bracing in your link is a lot easier but results in very large panel areas that are unbraced and therefore free to resonate. This is still a good method though if you use a lot more pieces of wood in all 3 dimensions and glue them together where each set of 3 crosses. Essentially, it becomes a different type of matrix system, like below. That's just a partial representation to give you an idea. Still a lot of work. And there are still actually large panel areas unbraced. Personally, I think matrix plus a few strategic cross braces would be best. Lots of other opinions out there though.
Attachments
Looks good but please note the correct dimensions, thanks.
I guess the BR port will go under the woofer, right?
Attachments
do you know your precise listening height measured where you plan to sit ?
and ofcourse in whatever position you normally take 😀
and ofcourse in whatever position you normally take 😀
Ok Felipe, here are some graphs for you.
Simulations are based on a 3m listening distance with the tweeter at about ear height. Dimensions and driver positioning are based on the last diagram you posted. For the woofer, I have only used about 3dB of baffle step compensation. In your room, it may need more or less. The mid is modeled in a sealed cab of 10L. The woofer in 75L tuned to 26Hz.
I used a reliable 3rd party (Zaph) for measurements of the tweeter and woofer, but had to rely on ScanSpeak's data for the mid. That's a good company though and my experience is that their's are better than others so I'm hoping it's accurate.
The xo to the woofer is at about 250Hz since distortion is best below 300Hz.
Graph 1 is your current speaker as is.
Graph 2 is with your current xo plus new xo's for the woofer. Not very pretty.
Graph 3 is my best attempt re-working all xo points. That's looking better but the top end still isn't very smooth due to the baffle diffraction of your top cabinet.
Graph 4 then is the top cabinet with chamfered edges like I mentioned before and then the xo optimized for that. Clearly that is the smoothest response. Minimum impedance gets down to about 3ohm just at 1 point around 5000Hz. If your amp can drive 4ohm speakers then that will be fine.
So time to make some choices. Let me know which version you want to go with - top cabinet as is or with chamfered edges. You could leave it as is and place felt on the front of the baffle to control the diffraction (like Wilson Audio does), but I have no way of modelling that result so no way of knowing what to do with the xo for that situation.
Cheers
Simulations are based on a 3m listening distance with the tweeter at about ear height. Dimensions and driver positioning are based on the last diagram you posted. For the woofer, I have only used about 3dB of baffle step compensation. In your room, it may need more or less. The mid is modeled in a sealed cab of 10L. The woofer in 75L tuned to 26Hz.
I used a reliable 3rd party (Zaph) for measurements of the tweeter and woofer, but had to rely on ScanSpeak's data for the mid. That's a good company though and my experience is that their's are better than others so I'm hoping it's accurate.
The xo to the woofer is at about 250Hz since distortion is best below 300Hz.
Graph 1 is your current speaker as is.
Graph 2 is with your current xo plus new xo's for the woofer. Not very pretty.
Graph 3 is my best attempt re-working all xo points. That's looking better but the top end still isn't very smooth due to the baffle diffraction of your top cabinet.
Graph 4 then is the top cabinet with chamfered edges like I mentioned before and then the xo optimized for that. Clearly that is the smoothest response. Minimum impedance gets down to about 3ohm just at 1 point around 5000Hz. If your amp can drive 4ohm speakers then that will be fine.
So time to make some choices. Let me know which version you want to go with - top cabinet as is or with chamfered edges. You could leave it as is and place felt on the front of the baffle to control the diffraction (like Wilson Audio does), but I have no way of modelling that result so no way of knowing what to do with the xo for that situation.
Cheers
Attachments
Chamfered edges 45º? onlyt top & sides?
My mono amps can drive 4 ohms (Borbely Millenium 75W RMS Class A @ 8 ohms), current speakers Wilson Audio Cub 4 ohms.
My mono amps can drive 4 ohms (Borbely Millenium 75W RMS Class A @ 8 ohms), current speakers Wilson Audio Cub 4 ohms.
Last edited:
I am not 100% sure but yes, I think a 2cm 45º chamfer on just the top and sides will be ok. That should just be a very small difference.
Perhaps as a test to know if my sims are matching reality, you might try your current xo with the 2.2ohm or the 3.3ohm resistor removed. This will bring the tweeter level up to about the same level as the mid. If you think it sounds better then we're good. If you think it sounds too bright, then we probably have a problem somewhere. Graph shows my sims with your current xo with the 3.3ohm removed.
Attachments
- Status
- Not open for further replies.