Fullrange Bipole MLTL speaker build

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This is a nice design and bit smaller than previous build.

Many thanks. :)

The primary reason it's smaller / shorter is because it was conceived as a quadrupole formed from two stacked modules, and I needed to keep the forward-firing driver near a typical ear-height. That's also the reason for the square cross-section; it ensures the same behaviour in each of the four radiating planes (as well as making construction a bit easier). A single module works fine as a bipole of course. Remember to wire the drivers in-phase though or you'll have no output from the enclosure. ;)

Do note that the design Scott just did was for Alpair 7ms and Pluvia 7HD, not your P7 but i fully expect it will fit with maybe a small change in the vent (restricted terminus).

We're in luck for once -with this box, even easier: no change necessary, they're a drop-in. :happy1:
 
frugal-phile™
Joined 2001
Paid Member
The primary reason it's smaller / shorter \

Do note that this new box is VERY similar to our original miniTower tribute ML-TL.

That is immediatly suitable for the P7 and like the new one can be stacked into a quarapole (or dual driver bipole — as in 2 drivers front & back), it will have the same configuration as the EL70.

dave
 
After couple of weeks of waiting, I have finally received the Pluvia 7 drivers. I went ahead and installed the new drivers in the cabinet. So far so, they are good, I do need to break them with few hours of use.

Depends on your amp. Each brings different compromises.

dave

To your question Dave, I am currently using Pioneer VSX-324 AVR as the stereo amp.

For now, I have wired them in Series. This should mean two 8ohms drivers would result in 16ohms. I am not really sure, if I should go for 16ohms or 4ohms. Which would be better?
 
Try both to see if there’s any difference in sound. If you’re using only in 2 channel mode, I’d think you’d be safe enough running in parallel for a nominal 4ohms. On the entry level of any brand of surround receiver, it’s probably a safe bet to de-rate the published power spec, even when running only in 2 channel mode.
If/when adding surrounds, you need to be more careful as to load impedance.
 
Try both to see if there’s any difference in sound. If you’re using only in 2 channel mode, I’d think you’d be safe enough running in parallel for a nominal 4ohms. On the entry level of any brand of surround receiver, it’s probably a safe bet to de-rate the published power spec, even when running only in 2 channel mode.
If/when adding surrounds, you need to be more careful as to load impedance.

Thank you Chris,

I think I will go ahead and build the second cabinet now and wire that for 4 ohms load, that way I can compare between 4 and 16ohms.

Yes, I am planning these for stereo pair no surround setup. The AVR that I am using is temporary setup for stereo and planning to replace it with Sansui AU-517 when I can get it.
 
Finally!!

I managed to build the second cabinet yesterday and completed the setup.
Although, I only realised after the second cabinet was done, that the first cabinet port size measurements were off when cutting the wood. And also the panels were slightly different in size by 5mm :(.
As a result the first cabinet bass output is bit boomy. I may work around a way to make that port size littler smaller.

Anyway both cabinets are built, and I ended up going the 4ohms route, since they sounded punchy and tight vs the 16ohms which sounded more loose but with more frequency response. The difference was very minimal.

I installed the drivers only yesterday, so have not had a chance to break in, but my God, it is a huge improvement to previous Dayton audio drivers I had in them.

Thank you Dave, Scott, Chris and others for your help and suggestions. So far so, I am finding difficult to leave these speakers alone, but with everyone at home due to lockdown it is hard to turn up the volume to truly enjoy them.

Question in regards to placement. How far away from wall would you recommend for speaker placement. Given the port is located in front, I doubt it will impact the bass output but due to bipole nature the other frequencies may be impacted depending where they are placed.
 

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frugal-phile™
Joined 2001
Paid Member
They should certainly be out more than in this picture:

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When you get some time to play (after break-in) start pullin gthem out little by little and see where you like them. There may well need to be a compromise between best for sonics and best for living in the room.

Is their. bird in the covered “box”? on the 3-ways?

dave
 
The “acoustic” foam might not be giving you as much damping as you hope, and bipoles definitely need more breathing space to back/ side walls than apparent in photos. I’d start at around 1/2 metre and play from there; and splashing the rear drivers’ reflections with few degrees of toe-in (5-10dg?) could add spaciousness to image.

I built two pairs of the original micro-towers to which Dave alluded earlier - one with second driver end-loaded, which I found to have far greater versatility in terms of room placement, and opted for an angled top on at least 4 subsequent builds with various Mark Audio wideband drivers, and even my current 2-way MTM variants.
 
The “acoustic” foam might not be giving you as much damping as you hope, and bipoles definitely need more breathing space to back/ side walls than apparent in photos. I’d start at around 1/2 metre and play from there; and splashing the rear drivers’ reflections with few degrees of toe-in (5-10dg?) could add spaciousness to image.

I built two pairs of the original micro-towers to which Dave alluded earlier - one with second driver end-loaded, which I found to have far greater versatility in terms of room placement, and opted for an angled top on at least 4 subsequent builds with various Mark Audio wideband drivers, and even my current 2-way MTM variants.

OK, Thanks Chris for the advise, I will play around the placement after few days to give them a chance for break in.
 
Ok, these are bit boomy to my taste.

Where should I put the stuffing? behind the drivers, near up top or near the port at bottom?

By the way, any tips for keeping the stuffing up top without them falling down and coming out of the port.

Since my woodworking skills aren't great, I was not able to make the cabinet with removable panel to adjust the stuffing, they are glued shut. But I can still add the stuffing after removing the driver.
 
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