I've seen a project where the construction was entirely symmetrical - a front and back MTM bipole. But is the addition on a rear tweeter really necessary?
You won't be achieving onmi dispersion. All it does is to even out the directivity index. Is that a good thing? Consider also that much of this amounts to spaciousness, similar to what is expected of a dipole. Such a diversity of early higher frequency reflections might benefit some arrangements and tastes, and some not.
I'd advise you to consider whether you like that sound of spaciousness.
I'd advise you to consider whether you like that sound of spaciousness.
Can't matter a whole lot for a high tweeter, but reading Linkwitz and Toole, and being simpler to do that to omit it, likely a good move.
B.
B.
So, we need that tweeter for the full deal, no matter if highs might get absorbed by the rear surfaces?
I need exactly that spaciousness sound + bass sensitivity gained from the lack of BSC for compatibility with low power tube amps. I'm the guy who rarely sits on a sweet spot and just roams from task to task around the room.
I need exactly that spaciousness sound + bass sensitivity gained from the lack of BSC for compatibility with low power tube amps. I'm the guy who rarely sits on a sweet spot and just roams from task to task around the room.
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Toole's (and I suspect Gedlee's) POV is that the total power reaching you from the speaker should be uncoloured. So helping keep the rear radiation uncoloured should be beneficial esp for the main seat which is always getting flat direct sound.
You are right about rear highs getting aborbed more. But you haven't provided us with any notion of your crossover frequencies.
B.
You are right about rear highs getting aborbed more. But you haven't provided us with any notion of your crossover frequencies.
B.
Ben, what difference does the crossover frequency make? There have been two options mentioned, baffle compensation only or full range.
A rear tweeter coming in at 6kHz adds very little music (and gets absorbed a whole lot more) than one coming at 3kHz.
B.
B.
Well, I will aim to cross at the lowest frequency possible, around 1.5kHz with a wave-guided tweeter for the best vertical lobbing. So they will be a TM most probably, not MTM.
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Once again, this forum goes running in circles because the question wasn't specified properly to start with. And we forgot to demand clarification at the start.
If you are going to crossover at 1.5 Hz, I bet most everybody would say "Of course your dipole needs that rear tweeter".
B.
If you are going to crossover at 1.5 Hz, I bet most everybody would say "Of course your dipole needs that rear tweeter".
B.
Ben, there was a thread recently on using the bipole arrangement on only the baffle step frequencies, 2.5 way style.
This thread is asking whether it is proper to add the highs as well. It was suggested that the highs have their own control on the rear panel and therefore aren't essential but adding them can be a choice, either way can work.
This thread is asking whether it is proper to add the highs as well. It was suggested that the highs have their own control on the rear panel and therefore aren't essential but adding them can be a choice, either way can work.
Exactly! These add a layer of confusion as well!
And then comes the offset bipole. If it's a two way, should be the tweeter and midbass positions vertically reversed at the rear?
And then comes the offset bipole. If it's a two way, should be the tweeter and midbass positions vertically reversed at the rear?
rear MTM
This topic is also under my radar, if back-fire drivers help or not, either they are in bi-pole or di-pole configuration.
Screening for commercial speakers, I've found Sonus Faber Aida, with an MTM arrangement in the back. Looks like the mids are ported.
Professional Loudspeaker Aida | Sonus faber
This topic is also under my radar, if back-fire drivers help or not, either they are in bi-pole or di-pole configuration.
Screening for commercial speakers, I've found Sonus Faber Aida, with an MTM arrangement in the back. Looks like the mids are ported.
Professional Loudspeaker Aida | Sonus faber
With this style of speaker why don't we use the old Wharfedale up-firing tweeters for what was termed "Air" back in the 1950s?
Or use three tweeters front back and up?
Or use three tweeters front back and up?
50AE,
In latest issue of audioXpress, January 2021, Perry Marshall publish him OB project, "The Live Edge". Despite other good ideas, use tweeter on back.
Good writing with tons of explanation and know how.Speakers and Transducers and Lots More in Audio Development and Design with audioXpress January 2021 | audioXpress
... Personally, I prefer (for aesthetic reason may be 🙂 ) Front tweeter with dipole diagram, like ESS AMT 🙂
In latest issue of audioXpress, January 2021, Perry Marshall publish him OB project, "The Live Edge". Despite other good ideas, use tweeter on back.
Good writing with tons of explanation and know how.Speakers and Transducers and Lots More in Audio Development and Design with audioXpress January 2021 | audioXpress
... Personally, I prefer (for aesthetic reason may be 🙂 ) Front tweeter with dipole diagram, like ESS AMT 🙂
Thanks lordoff!
One of our local craftsmen, Daniel Dotsov, has built an MTM bipole which he called "The mirror". He made it completely symmetrical, with a tweeter at the back.
Sadly I'm in a long-occurred quarrel with their owner, so there's no chance I can directly listen to these. For now, at least.
You can check it out on this video: The Mirror - YouTube
One of our local craftsmen, Daniel Dotsov, has built an MTM bipole which he called "The mirror". He made it completely symmetrical, with a tweeter at the back.
Sadly I'm in a long-occurred quarrel with their owner, so there's no chance I can directly listen to these. For now, at least.
You can check it out on this video: The Mirror - YouTube
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