In need of a builder...

[voodooless]

A 6th-order bandpasses are severely bandwidth-limited. I'm not sure it's a good idea to run them up to 200 Hz. Bose thought it was a good idea though...

I would just go with the push-pull closed system. It will give you double the air moved vs Isobarik. You'll just need more power. The two Seas drivers will only need 36L to be happy. Even in 25L, they will do fine, maxSPL is the same, you'll just need about 350W and you'll still get 100+ dB at 30Hz. Coupled with room gain, that will be even better. That is very respectable for such a small box. And you'll have two!

You could also look at 4x 5.25/6.5" to complement the MTM in looks. You may also be able to utilize the full enclosure volume by simply adding a sound-absorbing barrier between mid and bass, blocking midrange, but bass not so much.

 

[BKr0n]

You could also look at 4x 5.25/6.5" to complement the MTM in looks. You may also be able to utilize the full enclosure volume by simply adding a sound-absorbing barrier between mid and bass, blocking midrange, but bass not so much.

Something like this? Only thing I would have to figure out is how to utilize the space inside and where to put the electronics. One idea is to just put the electronics in the stand, but that would mean I only have one stand to use for them. That and it would be a little bit wide (about 17" or so)

Also, you would be talking about equivalent cone surface area right? (with the 4 6.5")

 

[BKr0n]

So I think this is the shape. Would be more exciting except I still don't really have a lot of tools at the moment. On the bright side, this can much more easily be made with sheet stock. Sorry @kemmler3D no 3d printing on this one. Only things left I need to figure out is the port shape/direction/exit and decoupling the MTM from the rest of the chassis. That and all the little details. Maybe flare out the opening a bit for the subs, etc. And bracing. That's important lol

edit: actually may 3d print the MTM enclosure so I can have a more curved enclosure with less points of diffraction.

 

[BKr0n]

@voodooless If I'm just doing push-pull I have two questions:
1) Do I need to make a slit where the two drivers meet?
2) Would I need to redo the calcs for the enclosure? Or would the calcs for isobaric still work?

 

[voodooless]

This isn't at all what I was proposing. I was just proposing your original idea with the 2 (or 4) opposing closed drivers. Isolabric is just a waste of resources and doesn't really bring you a lot of advantages, especially in the day and age of DSP.

 

[BKr0n]

This isn't at all what I was proposing. I was just proposing your original idea with the 2 (or 4) opposing closed drivers. Isolabric is just a waste of resources and doesn't really bring you a lot of advantages, especially in the day and age of DSP.

I mean, tbf, it does allow for smaller enclosures by only needing half the Vas. Is this the same for a push-pull config?

Also, don't know how I feel about getting 4 more purifi drivers when two of the subs are less than half the price of one purifi 6" driver.

 

[voodooless]

only needing half the Vas

Well, yes, but you don't get more moved air, not more power handling, and it will cost you double.

Is this the same for a push-pull config?

No, it's just the same as a normal 2-woofer closed box.

getting 4 more purifi drivers

There are other speaker brands, you know?

 

[BKr0n]

Well, yes, but you don't get more moved air, not more power handling, and it will cost you double.

But wouldn't trying to compensate with just power mean I would need a lot more of it? I get that yes, DSP can more than compensate, but it can only compensate for so much. I would say 3db in sensitivity is worth it in extension.

With the Daytons in isobaric, at 100W, I can hit 20hz easily and not have to blow the power budget. It's also the only set of data that actually reaches that high in 20hz unassisted. I would still be able to have my dynamics at high volumes as well.

There are other speaker brands, you know?

I thought you meant to go with purifi to "compliment the looks" my bad. Although, I do think it would be better to stick with a driver that is made to be flat at the low end. That's why I picked the seas originally. But with the Daytons I can get similar performance at half the cost.

 

[voodooless]

With the Daytons in isobaric, at 100W, I can hit 20hz easily and not have to blow the power budget

Hitting 20 Hz is never a problem. Getting significant SPL is.

As for your 20Hz tuning: you'll need quite a bit of volume for that port. It's going to be quite big if you want adequate airflow.

 

[BKr0n]

Hitting 20 Hz is never a problem. Getting significant SPL is.

I mean, the objective of the build is to have as little distortion as possible and flat response throughout the audible band. Doesn't really matter to me what the technique is as long as it performs and does what it needs to. Don't need it SUPER loud, but yes would like some SPL. With that said then, would I even need another driver? Or would one Seas driver do the trick?

 

[voodooless]

Or would one Seas driver do the trick?

Maybe, how loud do you listen on average, at what distance, and how low do you need it to go?

 

[BKr0n]

Maybe, how loud do you listen on average, at what distance, and how low do you need it to go?

So design-wise these are going to be work horse monitors. So anything from near-field to small or medium room. I'm going to be moving around a bit in the near future so I would like to not have to deal with floor-standers while doing a move.

 

[voodooless]

work horse monitors

Meaning what exactly?

So anything from near-field to small or medium room

What is a small and medium room.. seems to me, these words mean different things in different areas (even within a country)

I would like to not have to deal with floor-standers while doing a move

Seems like you could just sacrifice extension for output and usage of space, or the other way around.. you'll need to figure out what compromise to make..

 

[BKr0n]

Meaning what exactly?

I keep forgetting some colloquialisms don't exist everywhere. I want to use them for everything from critical listening to watching movies and playing games. Hence why I want as much extension as possible within a small footprint (a shame they don't make the tymphany LAT anymore huh?)

What is a small and medium room.. seems to me, these words mean different things in different areas (even within a country)

Again, me forgetting there's other countries than the US like a room to watch TV in (not sure if family room or den are universal)

Seems like you could just sacrifice extension for output and usage of space, or the other way around.. you'll need to figure out what compromise to make..

Here we arrive at the crux of the matter! lol. That's where I've been running in circles.

There's a marginal difference between having one or two woofers in the enclosure, and isobaric or not, for either more or less space. Only difference is two woofers would give me +9db of sensitivity (two woofers, parallel at 2 ohms). With that sensitivity I suppose I could supplant that with a higher power budget. So really I should just pick one of the previous designs and, instead of making a ported enclosure, make it sealed... HURRAY I WENT IN A BIG CIRCLE!!!

 

[voodooless]

Again, me forgetting there's other countries than the US

I specifically did not say "countries". Even within the US, this may differ. A small room in Manhattan will mean something else than on a farm in West Virginia

Only difference is two woofers would give me +9db of sensitivity (two woofers, parallel at 2 ohms)

6 dB, not 9.

You should not just look at the sensitivity and SPL curves. Compare MaxSPL to see how much output you'll potentially get. It will tell you how much headroom you have to EQ the thing.

 

[BKr0n]

You should not just look at the sensitivity and SPL curves. Compare MaxSPL to see how much output you'll potentially get. It will tell you how much headroom you have to EQ the thing.

Two of the Seas woofers wins that one again. So yeah... biiiiiiiiiiiiiiiiig circle. Then again, not the first time doing all this so I'm gonna put this one up as a learning experience.

Edit: By that rationale, wouldn't just using super sensitive woofers be a better answer, and then just EQ them with DSP?

 

[Salt]

. biiiiiiiiiiiiiiiiig circle

True. Running around it for several rounds ....

 

[BKr0n]

True. Running around it for several rounds ....

Eh. Like I said, learning experience. I would rather bang my head against the wall a little bit and actually learn these concepts than not. Otherwise I would be making a design that makes no sense.

 

[Salt]

Repeating myself: do investigate some literature and then begin ...

 

[voodooless]

Edit: By that rationale, wouldn't just using super sensitive woofers be a better answer, and then just EQ them with DSP?

No, that doesn’t work like that. It won’t be super sensitive where you need it to be.