Since Dave didn't immediately pipe in, let me opine that you could theoretically implement a dipole with any driver that is not itself sealed, but with various degrees of success - but I think you probably mean bipole. I think whether that's an appropriate approach rather depends on the specific application - i.e. your room /listening habits & tastes.
From my personal experience with the A7 ( I have a single running right now as center channel in a small HT system, and prior to that spent a fair bit of time listening to them at Dave's place), as well as several configuration of bipole designs over the past few years, I'd imagine a pair of A7 per enclosure could certainly raise some eyebrows.
re Tysen - the original concept of this particular design was to add a small woofer to a single wide-band mid-tweeter crossed over rather lower than "normal" , in as compact a footprint enclosure as the drivers could fit
but of course, one can't help but 'spose that more would be better - we just haven't got around to prototyping one yet
Tysen was carefully manipulated to make the simple driver selection work. The box, currently code named superTysen, will likely have 2 A7 in a variation of a bipole (a development of the Castle config) primarily for its ability to provide BSC and give more freedom on the XO point.
As a generalization, more bass. But each driver, in each box style, usually has a volume range that is optimum. For my ap somewhere between 5 & 9 litre for each A7. Each SDX7 will need about 14 litre effective volume.
dave
Perhaps it would be helpful to give my specific intentions for this build. I am looking to build my first pair of speakers for a living room that is roughly 16' x 16'. Being that i am young and have kids, it has all the family goodies like furniture, TV, entertainment system, and the ocasional temporary rocket ship tent. While we will be using these same speakers for watching TV, we listen to a lot of music and this is what i want to optimize them for. I would love to do dipoles but realize that my listenening situtation will not allow for it. I need speakers that are not super peculiar in term of positioning and sound awesome. Easy enough, right. The bipole is interesting for all the reasons above, but i am unsure about its depedence on positioning. I am just as willing to stick two A7's on the front if it will help with woofer integration, as I believe this is porbably a very good idea in terms of supplementing the FR driver I choose. I am a very skilled woodworker, so this is not a limitation. ANy problem encountered in this area can be supplemented by my local Quaker neighbor who could build a house with a knife and glue. I have been toying with the idea of doing something like the B&W nautilus designs for the A7's sitting on top of a cabinet like their 802 series. As i said, I am willing to do anything in terms of the enclosure, if it will help sound. I would love for you guys to do all the development work for me, but i understand you have other sucklings to attend to. 
THanks for the help so far!
THanks for the help so far!
A true bipole needs to be at least a couple feet out from the wall, and if not considerable wider than deep will have an on-axis bipole dip/suck out. Moving the 2nd driver to the top/side reduces these issues. 2 drivers on the front means having a filter on one driver to get the BSC, the hop is with side or top mount 2nd driver the BSC benefits can be had without a filter. And in my room i effectively have no ceiling bounce so top mounted makes sense (+ the castle microTower experiment worked so well)
dave
dave
I was only speaking of the possibilty of a bipole in a super tysen type setup. This FAST based design is what intrigues me. In one thread, you spoke of a double A7 tysen with multiple woofers. This sounds interestiing but perhaps over my head for first build. I will do some reading a get back to you.
There are huge swaths of potential in FAST. I have posted a few examples & there are many others (many of them OB)
It is not all that different conceptually than the original Tysen. Bigger with 2xA7 & 4xSDX7 per box.
dave
Do TL's help smooth both the SPL response and the impedance response, beyond giving an improved bass response. Specifically why you would want to add one to the A7 portion of the Tysen considering the augmentaion of the bass. Will the bass section have its own TL somewhat like the Ariel speaker. How important is the angle on the front face of the driver in determining the improvement to baffle diffraction. Does it have to be a certain angle and how does this affect the response using larger or smaller angles. I am willing to be a guinee pig on this project assuming you tell me everything you know in the next of couple of days. Side note. My ceilings are 8ft. so i am unsure if the castle setup will work. I am also unwilling/unable to spend money on 4 woofers per speaker so maybe I can do a half-super tysen.
Side note. My ceilings are 8ft. so i am unsure if the castle setup will work. I am also unwilling/unable to spend money on 4 woofers per speaker so maybe I can do a half-super tysen.
The TLs are not for bass-extension. As a mid-TL they are damped opposite of a TL trying to achieve bass reinforcement (light behind the driver, getting progressively heaver as the terminus is approached, in the end trying to be aperiodic). The idea is to have a low pressure enclosure, with little or no reflection from the back of the driver, and a flattened impedance.
dave
dave
Male voice can reach down to 80 Hz.
If your mid-tweeter can handle the dynamics & upper bass "punch" required, going to 60-80 Hz would be a goal if male voices were the consideration. One has to compromise between max levels, dynamics, low XO point.
With the A7s in sTysen i think 100-200 hz is going to work.
Toole's work on bass in rooms would have mains 80Hz up, multiple mono woofers under that.
I am sure people will be, or already are using Alpair 10/12 like that. Lots of other candidates too.
dave
If your mid-tweeter can handle the dynamics & upper bass "punch" required, going to 60-80 Hz would be a goal if male voices were the consideration. One has to compromise between max levels, dynamics, low XO point.
With the A7s in sTysen i think 100-200 hz is going to work.
Toole's work on bass in rooms would have mains 80Hz up, multiple mono woofers under that.
I am sure people will be, or already are using Alpair 10/12 like that. Lots of other candidates too.
dave
While we have discussed the A7 to this point, it would seem that the A10 is better suited for low XO. Do you agree with this? Would double A7's accomplish similar results? In your original design, you have a side firing woofer placed high up and just down from the Mid/tweeter to help with phase alignment issues. In my personal situation, i will have furniture(Ent.C) to the inside of the speaker and on the outside as well(open design bookshelf). Will it be better to have forward facing woofer to help eliminate room interaction. Firing into 4pi space XO low, is this as important. It seems I remember that room interaction/gain is important down low.
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