Looks original.MisterTwister said:gainphile, no, I mean like in attached picture(speakers are wired with opposite polarity)

Did you try to turn one woofer by 180° as in this configuration?
Or connect them with same polarity?
Definitely wrong. See my link to Linkwitz above.MisterTwister said:why not? it may have same output as one woofer on H frame
Marginally.
... but you are getting reduced harmonic distortion and it takes about the same space as H or U frame (even less)
You don't have to worry about resonances in an equivalent H frame either.... and you don't have to worry about resonances.
"A single driver in an H-frame would have the same output if the distance D between the openings is 2d1"
well, I guess I got it all wrong
when drivers are attached back to back there is substantial decrease in harmonic distortion, at least based on my own measurements.
This arrangement may be even better (less space between drivers), see attached.
pacificblue, if you connect them with same polarity, you'll get no bass at all. they must fire in same direction
well, I guess I got it all wrong
when drivers are attached back to back there is substantial decrease in harmonic distortion, at least based on my own measurements.
This arrangement may be even better (less space between drivers), see attached.
pacificblue, if you connect them with same polarity, you'll get no bass at all. they must fire in same direction
Attachments
MisterTwister said:"A single driver in an H-frame would have the same output if the distance D between the openings is 2d1"
well, I guess I got it all wrong![]()
Sorry for my wrong estimate,
looking at the picture you provided I was under the impression that D would be almost two times 2d1. I just had a look at some drivers of mine, where d1 in most cases is almost the same as the drivers depth. So D~2d1 seems to be realistic.
Letting them fire in different directions should give a similar amount of bass as the front-to-front version with very little mounting distance, while reducing harmonic distortion further. Even more so in a front-to-back configuration that helps to cancel out speaker unlinearities and movements of the support construction.MisterTwister said:pacificblue, if you connect them with same polarity, you'll get no bass at all. they must fire in same direction
Tosh said:There used to be a smaller 2-way dipole project on Linkwitz' site, but I can't seem to find it anymore. I believe it used a Vifa 8 inch woofer and had a passive XO. Anyone remember it?
It´s the PMT1.
It's been a while and since then I learned about smaller OB implementation like PMT1, Manzanita, Phoenix main panel. I've also gone from 6" woofer, 8", u-frame, h-frame, dual 8". But what I learnt was not to skimp on Bass (with capital) and use simple baffle.
This is the latest iteration. I managed to remove the mid and replace it with a FR. It does not have as sparkling high so I'm still working on that. I learnt also that phase or acoustics alignment is very important. Once the alignment is heard it's hard to "unlearn" the experience.
It's a 15" eminence but still looks reasonable on top of my desk and I can still do work/study. There are two variants of XO and compensation circuit. The first one is multi-staged and will produce 20Hz at -6dB but on some recording material would make the eminence bottom-out. So I opt for the less aggresive one.
This is the latest iteration. I managed to remove the mid and replace it with a FR. It does not have as sparkling high so I'm still working on that. I learnt also that phase or acoustics alignment is very important. Once the alignment is heard it's hard to "unlearn" the experience.

It's a 15" eminence but still looks reasonable on top of my desk and I can still do work/study. There are two variants of XO and compensation circuit. The first one is multi-staged and will produce 20Hz at -6dB but on some recording material would make the eminence bottom-out. So I opt for the less aggresive one.
if you happened to have a ton of power, I suppose you could do a ripole implementation of a high efficiency 12" woofer and then perch a 4" wide ranger in OB on top of it... still minimal depth, but probably greater low extension than a U of the same size, as fitting a very liberal definition of OB. Again, contingent on having an old beefy amp around.
I just built this particle accelerator with 15in daytons
http://img524.imageshack.us/img524/7307/cimg1331xh7.jpg
seems to output enough bass, have not measured it yet
I think, for tabletop, multiple drivers could be placed in the same arrangement (in one row, one after another). say 5-6 4.5in woofers.
http://img524.imageshack.us/img524/7307/cimg1331xh7.jpg
seems to output enough bass, have not measured it yet
I think, for tabletop, multiple drivers could be placed in the same arrangement (in one row, one after another). say 5-6 4.5in woofers.
Hi Mister Twister
I am more than curious as to your findings regarding the use of woofers in this fashion (SPL levels, equalization, etc). I bought myself fous units of an 18" PA woofer and any enclosure is to big for my small room. So now I am thinking about something along the lines of your idea/project for the bass. I will be using the threads/rods to hold two wooden beams in vertical position on which I will attach a MDF panel containing a B200 fullrange from Visaton. Something like the sketch (very flexible construction, BTW).
Erik
I am more than curious as to your findings regarding the use of woofers in this fashion (SPL levels, equalization, etc). I bought myself fous units of an 18" PA woofer and any enclosure is to big for my small room. So now I am thinking about something along the lines of your idea/project for the bass. I will be using the threads/rods to hold two wooden beams in vertical position on which I will attach a MDF panel containing a B200 fullrange from Visaton. Something like the sketch (very flexible construction, BTW).
Erik
Attachments
ErikdeBest, without baffle they loose spl too quickly, they can't keep up with my main speakers. I attached measurements from 20in distance-red and ~8ft distance-green(with turned up amp gain knob). I am going to try to put these subs closer to where I sit.
Attachments
Hi MisterTwister
I was already expecting that they would lose SPL too quickly, but as I will use them in a small room at relatively low sound levels I hope I can accomplish something nice. I hope their 18" size will help a bit as well...
Whenever I finish building them according to my sketch in the earlier post, I can always try to add some baffle (although I do not know exactly where...)
Erik
I was already expecting that they would lose SPL too quickly, but as I will use them in a small room at relatively low sound levels I hope I can accomplish something nice. I hope their 18" size will help a bit as well...
Whenever I finish building them according to my sketch in the earlier post, I can always try to add some baffle (although I do not know exactly where...)
Erik
ErikdeBest said:Hi Mister Twister
I am more than curious as to your findings regarding the use of woofers in this fashion (SPL levels, equalization, etc). I bought myself fous units of an 18" PA woofer and any enclosure is to big for my small room. So now I am thinking about something along the lines of your idea/project for the bass. I will be using the threads/rods to hold two wooden beams in vertical position on which I will attach a MDF panel containing a B200 fullrange from Visaton. Something like the sketch (very flexible construction, BTW).
Erik
Legacy Whisper did just that . Here's a clone project link http://www.htguide.com/forum/showthread.php4?t=3587&highlight=whisper
Re: sideways ripole?
Sound propagation does not work like you intend. You can´t force bass "around the corner". A H frame of the same outer dimensions might be a better solution.
PeteMcK said:Given that the Ripole is the most compact OB, how about modifying as per sketch attached ...
Sound propagation does not work like you intend. You can´t force bass "around the corner". A H frame of the same outer dimensions might be a better solution.
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