Hooters
Here's 1 of my 2 pairs on a scrap MDF board .
I'll use this (admittedly not optimal) dipole setup as a basis to compare my ripoles. I should probably flip the mdf board so that the drivers are closer to the floor. Luckily, the drivers I got had the push/Clip type binding posts so re-configuring drivers should be easy.
Initial impressions, .. not as deep or efficient as the tuba horn in the background, ....though this setup is nowhere optimal. However, the bass is punchy and does extend down to the high 30s at least.
The bass is strong and even sounding, .. no major peaks to worry about, ... probably because it nukes the room modes that have been bothering me. Also, the bass is not floppy or woolly sounding. Running a frequency sweep at the listening position, I see that it's moderately even with a sharp null around 65 Hz, which is not an audible problem. I suspect this is placement related.
More to come
Here's 1 of my 2 pairs on a scrap MDF board .
I'll use this (admittedly not optimal) dipole setup as a basis to compare my ripoles. I should probably flip the mdf board so that the drivers are closer to the floor. Luckily, the drivers I got had the push/Clip type binding posts so re-configuring drivers should be easy.
Initial impressions, .. not as deep or efficient as the tuba horn in the background, ....though this setup is nowhere optimal. However, the bass is punchy and does extend down to the high 30s at least.
The bass is strong and even sounding, .. no major peaks to worry about, ... probably because it nukes the room modes that have been bothering me. Also, the bass is not floppy or woolly sounding. Running a frequency sweep at the listening position, I see that it's moderately even with a sharp null around 65 Hz, which is not an audible problem. I suspect this is placement related.
More to come
An externally hosted image should be here but it was not working when we last tested it.
Re: Hooters
If that baffle was twice the size, you would get considerably better bass extension.
Mine were also very smooth throughout the entire range up to 125Hz where they were crossed over. The only thing I had to do was use a bit of EQ to lower the output around the xover freq just a little.
The 65Hz null you have is mostly due to your room more than just placement. If it's a sharp roll-off, that's what would be known as a "suck-out". I'm not sure if there's anything that can be done about that other than heavy room treatments. Trying to EQ it won't do anything but overdrive the signal and drivers, and very little if any to improve it.
zobsky said:
If that baffle was twice the size, you would get considerably better bass extension.
Mine were also very smooth throughout the entire range up to 125Hz where they were crossed over. The only thing I had to do was use a bit of EQ to lower the output around the xover freq just a little.
The 65Hz null you have is mostly due to your room more than just placement. If it's a sharp roll-off, that's what would be known as a "suck-out". I'm not sure if there's anything that can be done about that other than heavy room treatments. Trying to EQ it won't do anything but overdrive the signal and drivers, and very little if any to improve it.
Re: Re: Hooters
I agree about the larger baffle = better bass. I just used that 2 x 4 board for evaluation because it was $0.50 scrap at home depot.
The null I talk about isn't bothersome, so I'm not going to dwell upon it any more for now. We'll see how things work out when I start building the ripoles.
chops said:
I agree about the larger baffle = better bass. I just used that 2 x 4 board for evaluation because it was $0.50 scrap at home depot.
The null I talk about isn't bothersome, so I'm not going to dwell upon it any more for now. We'll see how things work out when I start building the ripoles.
johninCR said:
Hi sorry for little OT
from what i see you know what you talking about. I have question about driver for OB sub /i mean from Thiele small POV/- i read too match different opinions about QTS /lets say 15''/ somebody say 1+ /martin king/ somebody the less the better
- totally different directions.
So where is good point to start - get the good drivers and than just attenuate baffle enclosure to match room and taste
Thank you very very much
Tomas
theAnonymous1 said:
Hopefully, my ripoles won't end up as a big flop and others can benefit by my experiment. I feel your pain about being limited by an apartment. Been there, done that.
In any case, my construction thread is here (not much there , YET)
http://www.diyaudio.com/forums/showthread.php?s=&postid=1308576#post1308576
In OBs there is no "one size fits all".tomtom said:
If you look closer you might find a system behind the different opinions: Real open (and small) baffles are a big shortcut for bass energy. To regain bass, you need a high Qts - or some heavy electronic equalisation which is expensive to achieve with passive components.
If you use some kind of frame (U, W, H) bass response is less attenuated. Especially in a ripole the combination of acoustic mass loading and passive filter will result in a bass response that doesn´t need help from the driver Qts.
Hi,
"Especially in a ripole the combination of acoustic mass loading and passive filter will result in a bass response that doesn´t need help from the driver Qts."
That is simply not true. Even Ripoles can´t defy the laws of physics.
Higher Q always means more output at the Fs. In a ripole it means less, or even no lowbass-equing with a very high Qt-driver.
jauu
Calvin
"Especially in a ripole the combination of acoustic mass loading and passive filter will result in a bass response that doesn´t need help from the driver Qts."
That is simply not true. Even Ripoles can´t defy the laws of physics.
Higher Q always means more output at the Fs. In a ripole it means less, or even no lowbass-equing with a very high Qt-driver.
jauu
Calvin
Distance from the rear wall.
I was planning on taking measurements on some variations of a dipole sub . Would there be any preferable specific distance to use ( front baffle from rear wall ) that would help to compare the results with what others have done?
I was thinking of using 3 feet (?).
I was planning on taking measurements on some variations of a dipole sub . Would there be any preferable specific distance to use ( front baffle from rear wall ) that would help to compare the results with what others have done?
I was thinking of using 3 feet (?).
Since nobody else seems to care 
:
I would recommend to take measurements in the opening plane(s) of the manifold. These will not show the dipole roll-off, but the 6dB roll-off is predictable. And it is the only measurement in a room that will be sufficiently free from room effects.
Next is a measuring distance of 1 m - preferably gated to exclude first reflections from font and side walls. It would be advisable to place the sub in the middle of the room for this.
You could take measurements at your listening position. They will not be really comparable to measurements in other rooms, but you could see how "flat" you manage to get compared to others.
There is really no sense in measuring with a specific distance to front or side walls. Individual room width and depth will have too much influence already with such configuration to make it comparable to other rooms.
:I would recommend to take measurements in the opening plane(s) of the manifold. These will not show the dipole roll-off, but the 6dB roll-off is predictable. And it is the only measurement in a room that will be sufficiently free from room effects.
Next is a measuring distance of 1 m - preferably gated to exclude first reflections from font and side walls. It would be advisable to place the sub in the middle of the room for this.
You could take measurements at your listening position. They will not be really comparable to measurements in other rooms, but you could see how "flat" you manage to get compared to others.
There is really no sense in measuring with a specific distance to front or side walls. Individual room width and depth will have too much influence already with such configuration to make it comparable to other rooms.
Thank you Rudolf. Yes your suggestions are right. I'll put up some measurements and pictures as soon as I have them.
I can't get the dipole sub off my mind and so I have to get them tested soon !
I had tested a dipole planar last year and it sounded great. It's been in storage for various reasons and will be brought out again sometime soon. I've just started on an 8inch driver and 1 inch dome OB . Hope to get it working soon.
Cheers,
Ashok.
I can't get the dipole sub off my mind and so I have to get them tested soon !
I had tested a dipole planar last year and it sounded great. It's been in storage for various reasons and will be brought out again sometime soon. I've just started on an 8inch driver and 1 inch dome OB . Hope to get it working soon.
Cheers,
Ashok.
I've been thinking about a ripole design for a long time. The very compact nature of the enclosure is appealing to my curring project. I have a pair of Tempest 15" woofer that I plan to load into a ripole W enclosure. I was reading their website again...seems there is a substantial loss of output with these enclosures. Their woofer has a sensitivity of 88db/watt, but in a ripole that drops down to 80!! Am I not reading something correctly?
jimluu said:
Yes,
you will have a fair bit of efficiency drop with a ripole. Do let us know how it turns out if you build one. I ended up building a pair of W-U stuffed hybrids (awaiting power amp, .. old amp died just as I finished the enclosures) , as my drivers didn't work very well in a ripole (too high Qts of 0.7, .. your tempests should be better suited) , . bass went moderately low but no slam, and too low efficiency to keep up with the arrays.
The W-U are good to an honest 30 - 35 Hz, .. .though I still need the horn sub for home theater style bass-slam.
Attachments
zobsky said:
Hey Zobsky, have you tried your hybrids near the side walls/corners of the room at all, or just in the middle of the room as in the picture above?
The reason I ask is because my original dipole subs using the PPA15's produced some serious bass right along side the side walls and about 3 feet out from the front wall. Then again, my H baffles were considerably larger than your W-U hybrids.
I see you get honest output down to about 30Hz or so, but how do they sound overall? And how high do you have them crossed over?
BTW, I don't know if you noticed, but I built some more huge OB's for myself again. Here's the link to my thread...
http://www.diyaudio.com/forums/showthread.php?s=&threadid=111318
chops said:
Hi,
I've tried varying the position a little but not to much, as the corners aren't free and one side wall is flanked by a door and the other by a large mirror, so I don't have too many placement option . Off topic, but FWIW, I couldn't hear any improvement when using a linkwitz (cone to magnet) mounting pattern, . so that's why I used a symmetric mounting pattern.
I hesitate to give a full review because this is still a work in progress and my power amp is dead (waiting for a replacement) but in any case, .....
These were actively crossed over between 80 and 100 Hz (either 2nd order or 4th order, depending on which crossover I used). I'm not happy with them crossed too much higher higher (breakup / resonant sound) The baffles are stuffed with polyfill. They sound good within their passpand (punchy and clean) though I get the feeling that there's still a little bit of resonance even below that (not sure if it's the room or the sub - most subs I've had in this room have that issue). I still want to brace a wall or two in the rear. Their intended application will be mid-bass cabinets ie. 100-120 Hz to 40 Hz (my arrays roll off naturally below 100 Hz anyway) . A horn sub will provide the goods below that. Once again, this is a work in progress.
Good job on the new monster OBs. If only I had more rooms at home, I'd be churning out more projects.
Noob alert!!
I was reading this thread but it looks like it fizzled out.
I was reading here because an idea for a project I've been looking at was called a 'ripole'. It looks a lot like the W design mentioned here.
But with differences. I'm working on an IB project. If the restrictions of the openings' CSA's discussed in this thread are all taken away leaving wide open forward and rearward flow, and if the rearward flow is attached to another room, an attic, or a basement, would this be an IB, a ripole, or a ripole IB?
I was reading this thread but it looks like it fizzled out.
I was reading here because an idea for a project I've been looking at was called a 'ripole'. It looks a lot like the W design mentioned here.
But with differences. I'm working on an IB project. If the restrictions of the openings' CSA's discussed in this thread are all taken away leaving wide open forward and rearward flow, and if the rearward flow is attached to another room, an attic, or a basement, would this be an IB, a ripole, or a ripole IB?
An externally hosted image should be here but it was not working when we last tested it.
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