Pipedream

[johnny5jz]

I finally got around to finishing these. I tried to use a gloss black with a metallic flake grey, but they look pretty similar, not like what was on the can. They look fine for now, but I will probably redo them at some point. I have spent a bunch of time with these, and they are a lot of fun. The soundstage is so wide, but the top end is lacking a bit of detail. Really only noticeable when comparing directly to other more detailed speakers. Right now I have them as rear surrounds, and they really shine there.

[djg]

https://www.linkwitzlab.com/LXmini/Gallery.htm

[Steve Lee]

White Duratex tinted to match the furniture or walls?

[johnny5jz]

These speakers have been very fun to listen to. From what I have measured, these speakers have about an 84db sensitivity. What surprises me, is they seem much more lively and dynamic than any speaker with this low of sensitivity. The soundstage is so wide, it almost seems to wrap around you. The center image is locked on in a very wide range of seating positions. The bass is just right. I usually like a little lower extension, but I don't feel I am missing anything while listening to them. They also sound good at low levels, which my other lower sensitivity speakers do not do as well. The highs i thought would be sound a bit rolled off, which these did not. They were a bit surprising how good the top end extension was. The downside to these speakers probably is the fact that they need to be out in the room. You can see where I placed them in the pic below. Next step is figuring out how to finish these to make them not look quite as ugly. That may be tough. I do need to figure it out on these, because I have at least one maybe two friends that want a copy of these after hearing them.

[johnny5jz]

I ended up building separate boxes for the crossovers on this speaker. There was not much room in the towers for the crossover. I used some left over lumber and got something started.

[johnny5jz]

I have been spending a quite a bit of time with these speakers lately. I ended up with the circuit shown below. I backed off of the attenuation on the full range just like Wolf had originally pointed out. I went from 10ohms to 20 ohms and settled on 15.

[johnny5jz]

Thanks for sharing your test data. Have you taken any near field port measurements? I'd be interested to see how the SPL of the main port tuning frequency shifts up and down as you make these changes.

I have not done that yet. Just doing the sweeps, you could tell the stuffed and lined test seemed attenuated vs the others. My crossover components are coming tonight, so I may try that later this weekend. I would at least like to test empty vs the mineral wool. Sent from my SM-G973U using Tapatalk

[4thtry]

Thanks for sharing your test data. Have you taken any near field port measurements? I'd be interested to see how the SPL of the main port tuning frequency shifts up and down as you make these changes.

[johnny5jz]

I played with a few different damping/stuffing methods tonight. In the chart below you can see a few different methods. The blue line is an empty cabinet, the purple is cabinet bottom stuffed with polyfil and lined with polyfill batting (too much stuffing, moved port tuning down a few hz), turquoise is bottom stuffed with polyfill, and green is bottom stuffed with mineral wool. The mineral looks the smoothest without affecting the port tuning. I will go with that for now and see how it sounds.

[johnny5jz]

Looks like classic pipe harmonics to me, fortunately the stuffing appears to damp them well. Not to say that it will sound better stuffed though, I'd try it both ways.

I am experimenting with a few different damping techniques and will see what measures and sounds best. I will report back with my results. Sent from my SM-G973U using Tapatalk

[Billet]

Looks like classic pipe harmonics to me, fortunately the stuffing appears to damp them well. Not to say that it will sound better stuffed though, I'd try it both ways.

[4thtry]

Cool. Good luck with your project!

[johnny5jz]

Here is two impedance sweeps. One is an empty box (tube) and one is stuffed at the bottom and lined. When I did the measurements, I had a bit of stuffing in the bottom of the box, but I had not lined it yet. The measurements I did first were with an empty box and it had much larger dips.

[johnny5jz]

Looking at the dip at 211Hz and the next two dips up, my initial reaction would be that these are listening room resonant modes and not standing waves within the cabinet (internal). Where did you place the microphone when you made these measurements? Bill

I measured these outside about 4 feet off the ground. I just ran an impedance sweep tonight on an empty box. There are large spikes that match those dips. I stuffed the bottom of one and lined it, and the impedance sweep is pretty good. I still have a bit of work to do to get them to go away completely. Sent from my SM-G973U using Tapatalk

[4thtry]

Looking at the dip at 211Hz and the next two dips up, my initial reaction would be that these are listening room resonant modes and not standing waves within the cabinet (internal). Where did you place the microphone when you made these measurements?

Bill