Potential drawback with the additional monopole sub is that you'll loose the advantage the dipole has for not transmitting bass outside the room so much. No doubt very effective though, Linkwitz mentions such a configuration:
http://www.linkwitzlab.com/thor-intro.htm
Thanks for the PM, have replied
http://www.linkwitzlab.com/thor-intro.htm
Thanks for the PM, have replied
Have recieved info, will read later
Thats interesting, I haven't heard that before. So in a small bedroom like I'm testing this dipole in I won't be getting any low bass? It certainly sounds like I am but then I haven't measured anything.
How do things work out for outdoors? Low bass is certainly produced at outdoor concerts, no doubt using massive amounts of power and efficient subs but it is definately there. Or how about headphones?
I would like to have bass down to 20hz, so I know I'm getting all of it ! Will look into either sealed or an open ended TL. Figure the TL reduces cone excursion around tuning as does a reflex design. A small one tuned to 20hz might be difficult but there are (inefficient) drivers that can do it.
Thats interesting, I haven't heard that before. So in a small bedroom like I'm testing this dipole in I won't be getting any low bass? It certainly sounds like I am but then I haven't measured anything.
How do things work out for outdoors? Low bass is certainly produced at outdoor concerts, no doubt using massive amounts of power and efficient subs but it is definately there. Or how about headphones?
I would like to have bass down to 20hz, so I know I'm getting all of it
! Will look into either sealed or an open ended TL. Figure the TL reduces cone excursion around tuning as does a reflex design. A small one tuned to 20hz might be difficult but there are (inefficient) drivers that can do it.
Sorry, I did not make myself clear enough. DIPOLE bass is falling off rapidly below the lowest room mode. The only bass you can get below is MONOPOLE bass pressurizing the room as a whole. And that means inevitably "transmitting bass outside the room". So in your small bedroom you will need some monopole to reach down to 20 Hz. Or you need to have the dipole sub next to your ears - where it does not work as a dipole WRT your ears, only for the room.
Outdoors the lowest room mode is at 0 Hz, so a dipole would work as low as the driver allows.
In the room gain region a monopole gains efficiency when going to lower frequencies, so you don´t need the most efficient bass driver.
Outdoors the lowest room mode is at 0 Hz, so a dipole would work as low as the driver allows.
In the room gain region a monopole gains efficiency when going to lower frequencies, so you don´t need the most efficient bass driver.
Ok, thats clearer . The dipole sub is quite close to me but not pressed against my ear (its very loud like that!). Mabye only 1.7m away from my ears though at the moment, worried it might be too quiet for a bigger room, even with 2.
A sealed LT sub with the Dayton RSS315HF-4 is quite inexpensive to add though and can run off 1 of the 2 channels of a studio poweramp (other channel powering dipoles). Not big at all either, just 35L will work fine
. The dipole sub is quite close to me but not pressed against my ear (its very loud like that!). Mabye only 1.7m away from my ears though at the moment, worried it might be too quiet for a bigger room, even with 2. A sealed LT sub with the Dayton RSS315HF-4 is quite inexpensive to add though and can run off 1 of the 2 channels of a studio poweramp (other channel powering dipoles). Not big at all either, just 35L will work fine
Dr.EM said:Ok, thats clearer
This is what I would call close
:An externally hosted image should be here but it was not working when we last tested it.
It´s Markus´nearfield dipole, when he lived in Germany (taken from here).
That is close
Does anyone have any idea about using these in a ripole (or like what I built, W baffle thing):
http://www.monacor.de/typo3/index.php?id=84&L=1&artid=2069&spr=EN&typ=full
Looks like they could be quite good, just seem expensive for what they are; very ordinary build quality. Virtually no info about anyone using them out there. Have a nice shallow mounting depth which will help keep things compact and good sensitivity. Also high BL to Mms factor which I summise helps with transient response? Also low Fs so the opening can be large, it doesn't need lowering as in a true Ripole (large opening allows opposing driver mounting to lower distortion) Xmax isn't huge but a pair of 15" should shift some air regardless.
Does anyone have any idea about using these in a ripole (or like what I built, W baffle thing):
http://www.monacor.de/typo3/index.php?id=84&L=1&artid=2069&spr=EN&typ=full
Looks like they could be quite good, just seem expensive for what they are; very ordinary build quality. Virtually no info about anyone using them out there. Have a nice shallow mounting depth which will help keep things compact and good sensitivity. Also high BL to Mms factor which I summise helps with transient response? Also low Fs so the opening can be large, it doesn't need lowering as in a true Ripole (large opening allows opposing driver mounting to lower distortion) Xmax isn't huge but a pair of 15" should shift some air regardless.
Dr.EM said:
I know at least of two Germans who built ripoles with this driver. Look at the simulation results Axel Ridtahler provided.
If you would like to get the construction details you can email Axel for them. But he will charge a small fee for it.
Thanks for your response!
Certainly wasn't aware anyone had tried this already, couldn't find even sealed or vented designs through google (just one I think I saw)! So presumably it is indeed good for this application. Yes, I will either ask Alex or experiment myself with it if I decide to try these drivers. I may prefer a larger opening since that design goes extremely deep possibly at the expense of output. I believe a smaller opening = lower resonant frequency and lower sensitivity?
Certainly wasn't aware anyone had tried this already, couldn't find even sealed or vented designs through google (just one I think I saw)! So presumably it is indeed good for this application. Yes, I will either ask Alex or experiment myself with it if I decide to try these drivers. I may prefer a larger opening since that design goes extremely deep possibly at the expense of output. I believe a smaller opening = lower resonant frequency and lower sensitivity?
I don't know if this design is an N or W frame, but if it is an N then a W can be expected to have 3db higher efficiency and 6db more max SPL. Looking at the response graphs this would easily put the sub into typical a subwoofer efficiency region of about 86db with 8ohm wiring. Not bad at all, not really a downside here, its a relatively large box but it goes very low! Output would be limited compared to a similar effeciency arrangement in a sealed box though since excursion will be more significant in OB.
Yes, we will just have to assume this. It looks quite ideal though, the driver. Something interesting is that the technical drawing varies depending where you look. Specifically the mounting depth which is higher on the manufacturers page than quoted on most online retailers:
http://www.monacor.de/typo3/index.php?id=84&L=1&artid=2069&spr=EN&typ=full
170mm, and here:
http://www.bmm-electronics.com/Product.asp?Product_ID=4486
153mm.
I think it's just an error in the technical drawing though since the manufacturers page still lists 153mm mounting depth in text. Hopefully it is since the shallower the better for this!
http://www.monacor.de/typo3/index.php?id=84&L=1&artid=2069&spr=EN&typ=full
170mm, and here:
http://www.bmm-electronics.com/Product.asp?Product_ID=4486
153mm.
I think it's just an error in the technical drawing though since the manufacturers page still lists 153mm mounting depth in text. Hopefully it is since the shallower the better for this!
Rudolf said:This is what I would call close
An externally hosted image should be here but it was not working when we last tested it.
It´s Markus´nearfield dipole, when he lived in Germany (taken from here).
Wow, that is impressive.
What's the advantage of ripole vs other designs? I was considering building a simple sealed such as linkwitz http://www.linkwitzlab.com/thor-intro.htm
I will attempt to answer though someone may correct me later
Advantages,
lack of "boxy" sound
improved transient response (no group delay) leading to tightest bass
less audible outside of listening room/lower "noise pollution"
Disadvantages,
need large drivers/high Xmax to move enough air to get useful output
typically uses a lot of power
You would probably have to hear it to appreciate the differences fully. Its like the naturalness of bass from headphones but with all the slam of speakers
Advantages,
lack of "boxy" sound
improved transient response (no group delay) leading to tightest bass
less audible outside of listening room/lower "noise pollution"
Disadvantages,
need large drivers/high Xmax to move enough air to get useful output
typically uses a lot of power
You would probably have to hear it to appreciate the differences fully. Its like the naturalness of bass from headphones but with all the slam of speakers
Thanks
There doesn't seem to be any info available. Looking at the following design I was wondering why they have the magnet petrouding. I would like to possibly build this with a peerless such as the 830500 or 830844. Is the measurements of their box critical. Can I modify it to fit another driver?
http://www.lautsprechershop.de/hifi/index_en.htm?/hifi/ripol_en.htm
There doesn't seem to be any info available. Looking at the following design I was wondering why they have the magnet petrouding. I would like to possibly build this with a peerless such as the 830500 or 830844. Is the measurements of their box critical. Can I modify it to fit another driver?
http://www.lautsprechershop.de/hifi/index_en.htm?/hifi/ripol_en.htm
Hi Dr EM,
I noticed on post 93 you gave a link to some IPL drive units for sale that you thought might be suitable for a ripole design. I had the same idea so I bought 4 of them. I could not resist at £15.00 each. Although they are not the best made drive units ever made I think that they should provide some fun.
The specs are:
Qts; 0.24
Vas; 268l
95db/watt
160 watt
12" diameter
Fs; 27Hz
Reagarding ripole design:
With a 12" drive unit the front vent will be about 13-14" long/high, and 4-6" wide. Obviously there will be a maximum and a minimum distance between the drive units and thus width of the vent that will give the ripole effect. what are these dimensions. At some point with increased width, the ripole effect must disappear with no reduction in Fs and reduction in efficiency.
Does the ripole effect "scale with this change in width?
I noticed on post 93 you gave a link to some IPL drive units for sale that you thought might be suitable for a ripole design. I had the same idea so I bought 4 of them. I could not resist at £15.00 each. Although they are not the best made drive units ever made I think that they should provide some fun.
The specs are:
Qts; 0.24
Vas; 268l
95db/watt
160 watt
12" diameter
Fs; 27Hz
Reagarding ripole design:
With a 12" drive unit the front vent will be about 13-14" long/high, and 4-6" wide. Obviously there will be a maximum and a minimum distance between the drive units and thus width of the vent that will give the ripole effect. what are these dimensions. At some point with increased width, the ripole effect must disappear with no reduction in Fs and reduction in efficiency.
Does the ripole effect "scale with this change in width?
Hmm, interesting project, Zobsky. Is this effectively like adding moving mass to drop Fs?
Jim
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