Jordan MLTL port exit query

[Colin]

I'm planning to build a triangular version of the 31" JX92S MLTL by GM and would appreciate some input on how the port exits.

The port will exit from the floor of the MLTL, extending the tube below the bottom of the cabinet. So effectively it's enclosed by a cavity. The query is regarding a stand - I would like to make this by simply extending the enclosure walls downwards and 'venting' the whole area via three large holes.

Attached diagram probably makes this clearer.

In doing this, am I likely to cause this area to act like an additional resonant cavity with three ports? (I don't need to further load the MLTL's port as I'm going for an accurate roll off rather than any emphasis in the bass.)

[chrisb]

OK, Colin, this is a stupid question - but if the stands are permanent, why not just build the taller design?

Of course you could do something like this, per Jordan's UK site:



Your sketch suggests a triangular version, which would only slightly complicate the cutting of the deflector.

I made a pair of the 48" triangular enclosures a couple of years ago, and they certainly work.

[Colin]

The 'stands' are really just an extension of the enclosure wall, extended five or six inches to get the driver up to height and allow the port to clear the floor. The problem is then getting the sound out from inside the stand! I could forget extending the sides and simply build in legs but I prefer the look of this.

Opening up one side with a reflector is possible, albeit increasing the tricky angles to cut. Plus I was hoping not to load the port, I'm going to integrate with a sub so I'd prefer no emphasis in the bass.

Yes, I've built the 48" triangles and they work fine. Time to try the more accurate 31" version but, unlike the 48, the port isn't short enough to fit horizontally.

[chrisb]

Originally Posted by Colin

The 'stands' are really just an extension of the enclosure wall, extended five or six inches to get the driver up to height and allow the port to clear the floor. The problem is then getting the sound out from inside the stand! I could forget extending the sides and simply build in legs but I prefer the look of this.

Opening up one side with a reflector is possible, albeit increasing the tricky angles to cut. Plus I was hoping not to load the port, I'm going to integrate with a sub so I'd prefer no emphasis in the bass.

Yes, I've built the 48" triangles and they work fine. Time to try the more accurate 31" version but, unlike the 48, the port isn't short enough to fit horizontally.

How about a simple tripod table - i.e. a solid 32mm^2 post in each corner, with a hole for the down firing port?

or an elbow in horizontal port

[Colin]

Well, the tripod is what I'm trying to avoid. And I'd like to keep the purity of the port exiting straight down, no obstructions. Thanks for the ideas though. I'll go with the tripod if the original idea doesn't work.

I was going to build the rectangular cabinet you posted earlier but the Household Authorities are rather fond of the triangles and have been campaigning for their return.

[planet10]

As long as the holes are sufficienty large you should have no problem. If they triangualr enclosures are pushed back against the wall, you will onlty have 2 holes.

dave

[Colin]

Thanks, for that. They'll be 6"+ diameter. Glad to hear I'm not inadvertently creating more reflex ports!