Hi all,
I'm a newbie looking for answers.
I am about to either choose or build the tweeters for my line array project.
Most DIY ribbon tweeters I have seen have "open backs" to radiate sound both ways.
Is this a suitable design for a tweeter, meant to match midrange and bass speakers that are boxed in a traditional way? Or should all drivers in a speaker be "open baffle" for best results?
I am a bit suspicious about dipoles in general, since I don't really see how they can reproduce recorded sound correctly, but feel free to convince me!
/Magnus
I'm a newbie looking for answers.
I am about to either choose or build the tweeters for my line array project.
Most DIY ribbon tweeters I have seen have "open backs" to radiate sound both ways.
Is this a suitable design for a tweeter, meant to match midrange and bass speakers that are boxed in a traditional way? Or should all drivers in a speaker be "open baffle" for best results?
I am a bit suspicious about dipoles in general, since I don't really see how they can reproduce recorded sound correctly, but feel free to convince me!
/Magnus
If you're interested in learning about dipoles, I would start by reading and digesting these two websites:
www.linkwitzlab.com
www.musicanddesign.com
www.linkwitzlab.com
www.musicanddesign.com
is it wise?
Ok, I have looked into the concept before and found both sites quite interesting.
I understand that dipoles won't suffer from "box distorsions", and perhaps I shouldn't worry about all the delayed reflections, since it is explained that the human brain automatically ignores them...
But is it wise to use dipole tweeters together with boxed mids and bass? Any comments?
Ok, I have looked into the concept before and found both sites quite interesting.
I understand that dipoles won't suffer from "box distorsions", and perhaps I shouldn't worry about all the delayed reflections, since it is explained that the human brain automatically ignores them...
But is it wise to use dipole tweeters together with boxed mids and bass? Any comments?
Dipoles are not a panacea. What about edge diffraction and baffle resonances. Dipoles have as many problems as boxes do. And the claim that they "excite few modes" have been totatly debunked. There are a lot of false claims out there about dipoles. I am not totally opposed nor totally on board, but I do look at all the problems with my eyes open.
where possible, it's best to pattern-match
Always best to pattern match as much as possible, to get consistent power response. This means horns with horns, direct with direct, dipole with dipole, etc. Sometimes you can mix and match, like a midrange/treble horn matched to a 12" or 15" that's already beaming. This is possible because the beamwidth tapers as the 12" or 15" becomes directional, but does so slowly, rather than an abrupt transition at the crossover freq.
Another (becoming more common) combination that has some promise is dipole at lower frequencies and directional (horns, waveguides) in the higher frequencies where horns are more modest sized. This saves you the need for huge enclosures.
Always best to pattern match as much as possible, to get consistent power response. This means horns with horns, direct with direct, dipole with dipole, etc. Sometimes you can mix and match, like a midrange/treble horn matched to a 12" or 15" that's already beaming. This is possible because the beamwidth tapers as the 12" or 15" becomes directional, but does so slowly, rather than an abrupt transition at the crossover freq.
Another (becoming more common) combination that has some promise is dipole at lower frequencies and directional (horns, waveguides) in the higher frequencies where horns are more modest sized. This saves you the need for huge enclosures.
Hi Magnus,
Only your ears can provide the final dipole vs. monopole answer, but you can avoid mistakes and do-overs if you can find local audio stores or friends that have dipole line sources like Magnepan or Apogee, mixed monopole bass and dipole ribbon tweeter like DALI MegaLine, monopole bass and planars like VMPS or kits that follow Jim Griffin's line array design rules. The easiest DIY might be copying a well reviewed closed box Jim Griffin line array design using planar tweeters.
http://www.audiocircle.com/circles/index.php?board=127.0
http://www.audioroundtable.com/misc/nflawp.pdf
http://audioroundtable.com/ArraySpeakers/
If you DIY a monopole ribbon tweeter, you will need to have extensive rear sound absorption material to keep the rear waves from reflecting back upon the ribbon foil..
If you DIY a dipole ribbon tweeter, a full 3-way dipole line array design would match the best products.
Only your ears can provide the final dipole vs. monopole answer, but you can avoid mistakes and do-overs if you can find local audio stores or friends that have dipole line sources like Magnepan or Apogee, mixed monopole bass and dipole ribbon tweeter like DALI MegaLine, monopole bass and planars like VMPS or kits that follow Jim Griffin's line array design rules. The easiest DIY might be copying a well reviewed closed box Jim Griffin line array design using planar tweeters.
http://www.audiocircle.com/circles/index.php?board=127.0
http://www.audioroundtable.com/misc/nflawp.pdf
http://audioroundtable.com/ArraySpeakers/
If you DIY a monopole ribbon tweeter, you will need to have extensive rear sound absorption material to keep the rear waves from reflecting back upon the ribbon foil..
If you DIY a dipole ribbon tweeter, a full 3-way dipole line array design would match the best products.
Attachments
It's important to note that the "rear wave" issue is often looked at incorrectly.
A monopole radiates sound rearward as well-this is a key point that gets lost. However, it's rear radiation is limited to below the bafflestep region. Above, it only goes forward into 2 pi space. This is the source of the on axis/power response problem of a monopole.
The dipole solves this, however, more energy is radiated higher up in the spectrum, making placement/rear wall interaction more important.
If you read SL's and John k's site, as well as the thread/comments by Dr. Geddes and John k on cardioid bass, you'll see that the simulations below 100 Hz have trouble showing a clear advantage to a dipole vs a mono or cardioid. (That doesn't mean that one doesn't exist-but hey, we're scientists. There may be a subjective difference in dipole bass, but...)
However, there is a clear difference between a monopole and a dipole in the 100-1.5k range or whatever is the practical upper limit to dipole radiation. The radiation pattern/power response is more uniform (not considering the space into which the radiation is occurring). Rear wave absorption is not an issue with dipoles. Panel resonances are difficult to assess. The motion of a dipole panel will likely be higher, but there is generally less panel to radiate in a dipole. I think the winner would be design specific.
Which way to go? Difficult question. You have to build and listen to better examples of each to decide. No design is inherently better.
Maybe we can get a set of Orion's or NaO's at the next Burning Amp festival, as well as one of Dr. Geddes DIY horns. I will bring my RST panels if they are finished by then.
A well done line array would be cool as well
A monopole radiates sound rearward as well-this is a key point that gets lost. However, it's rear radiation is limited to below the bafflestep region. Above, it only goes forward into 2 pi space. This is the source of the on axis/power response problem of a monopole.
The dipole solves this, however, more energy is radiated higher up in the spectrum, making placement/rear wall interaction more important.
If you read SL's and John k's site, as well as the thread/comments by Dr. Geddes and John k on cardioid bass, you'll see that the simulations below 100 Hz have trouble showing a clear advantage to a dipole vs a mono or cardioid. (That doesn't mean that one doesn't exist-but hey, we're scientists. There may be a subjective difference in dipole bass, but...)
However, there is a clear difference between a monopole and a dipole in the 100-1.5k range or whatever is the practical upper limit to dipole radiation. The radiation pattern/power response is more uniform (not considering the space into which the radiation is occurring). Rear wave absorption is not an issue with dipoles. Panel resonances are difficult to assess. The motion of a dipole panel will likely be higher, but there is generally less panel to radiate in a dipole. I think the winner would be design specific.
Which way to go? Difficult question. You have to build and listen to better examples of each to decide. No design is inherently better.
Maybe we can get a set of Orion's or NaO's at the next Burning Amp festival, as well as one of Dr. Geddes DIY horns. I will bring my RST panels if they are finished by then.
A well done line array would be cool as well
Magnetar said:
Well, I guess that's open to debate. I don't disagree that dipole bass sounds different. But this is subjective. Nothing wrong with that. And, simulations are fraught with error.
I think you have to accept that the jury's still out. You can choose dipole bass over monopole if it suits you, but how clear the "measureable" advantages are is still a bit uncertain. I think if anything, proponents of dipoles have more ground to stand on in the 100-1000+ hz range. Or, at least that's the way I see it.
PS- I'm in my dipole phase. See my project at RST dipole
So, I'm not against dipoles. But let's try to not overgeneralize or state a preference, however based in science, as science/dogma
I've built SL's plutos, which are omni below 1000Hz and monopole above that. I've also built open baffle (dipole) wide range two-way with a B200 above 150Hz and an Alpha15 below (in an H frame). These are both decent designs among many, and major differences are probably design specific; but I can say one thing for sure - I seriously doubt I will ever make a boxed speaker again - open baffle/dipole is a very large step forward in spatial realism, and this seems to be an inherent trait of open baffle speakers, judging from the large number of people building them and saying so.
Just my two cents, but I highly suggest you try OB..
Just my two cents, but I highly suggest you try OB..
Re: am I right?
Yes you can have dipole above 1500 - you say most ribbon tweeters are dipole- I don't think so, most are monopole so you'd have to use twice as many - Maybe try monopole first then add some back tweeters to see how you like them. You could wire the back tweeters in and out of phase for bipole and dipole..
maghen said:
Yes you can have dipole above 1500 - you say most ribbon tweeters are dipole- I don't think so, most are monopole so you'd have to use twice as many - Maybe try monopole first then add some back tweeters to see how you like them. You could wire the back tweeters in and out of phase for bipole and dipole..
Maghen,
I'm raising Cuibono's 2 cents with 2 riksdaler...
For a long time I ignored dipoles, I didn't believe at all in the concept of open baffles. It just felt intuitively wrong to not have a box, and so I never offered them a thought.
Then last winter I finaly listen to a pair of them. My eyes were opened. In an instance I realized just how closed in and unnatural 99% of regular speakers sounds.
I know, it may sounds almost religious when people talk of OB sometimes. None the less, I much doubt I will use "regular" speaker as mains in my home again.
Regarding your ribbon question, I would definetly go dipole for the ribbon + dipole mid. In the bass region its kind of open, both dipole or monopole works.
I think it is a good idea to listen to a pair of dipole's and get yourself an opinion if you like it!
Good luck on your journy!
/Jon
I'm raising Cuibono's 2 cents with 2 riksdaler...
For a long time I ignored dipoles, I didn't believe at all in the concept of open baffles. It just felt intuitively wrong to not have a box, and so I never offered them a thought.
Then last winter I finaly listen to a pair of them. My eyes were opened. In an instance I realized just how closed in and unnatural 99% of regular speakers sounds.
I know, it may sounds almost religious when people talk of OB sometimes. None the less, I much doubt I will use "regular" speaker as mains in my home again.
Regarding your ribbon question, I would definetly go dipole for the ribbon + dipole mid. In the bass region its kind of open, both dipole or monopole works.
I think it is a good idea to listen to a pair of dipole's and get yourself an opinion if you like it!
Good luck on your journy!
/Jon
felixx said:
I want to build something like that! Do you have a build thread?
ion said:
I am with you. In some sense I 'wished' I hadn't played around with dipoles. It's impossible to unlearn the 'experience'. Anyone know it's really nice to have a good looking dynaudio or sonus in the living room.
In my opinion, if you listen to predominantly pop/rock - i.e music produced in a recording studio, then monopole is the way to go. After all thats what the sound engineers were listening to when they made the master tape. monopoles are also far more suitable for surround sound.
If you are more into jazz and/or classical, where you want to recreate the live ambience from a stereo pair, and you have a nice big listening room with room to keep the speakers well away from the walls, then dipole looks like a nice option. However, they are usually more complex in terms of amplication requirements.
www.gattiweb.com
If you are more into jazz and/or classical, where you want to recreate the live ambience from a stereo pair, and you have a nice big listening room with room to keep the speakers well away from the walls, then dipole looks like a nice option. However, they are usually more complex in terms of amplication requirements.
www.gattiweb.com
Gospel
Ok, enough preachin' for now
.. it's just so hard not to
Cheers!
Yes, I understand your point there and I do respect your opinion. However, I think that the acoustical properties of a regular living room and a controlled studio environment is far from interchangeable.David Gatti said:
My experience is actually quite the oppisite. I would argue that dipoles are superb for surround sound. One area where the dipole really excels is in the presentation of ambience. A dipole sourround setup throws a giant soundfield to be embraced in. Theres nothing like it, really!David Gatti said:
Ok, enough preachin' for now
.. it's just so hard not to Cheers!
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