Stereo Integrity's new HT Subwoofer - Page 40

That's funny because it says SI HT18D2 is 22.5mm and they still list 23.5mm in the spec list. Website needs to be updated. What are they doing over there, now that they've sold out of the most popular model? They haven't answered my last e-mail from about a week ago yet.

Qms is also very different - 5.8 (SI) vs 2.88 (Ricci)

In case anyone is looking for the EP4K, Walmart (Google found it, I never buy from there) has it for $275 right now: http://www.walmart.com/ip/17656014?adid=22222222227014431015&wmlspartner=wlpa&wl0=&wl1=g&wl2=&wl3=13698474550&wl4=&wl5=pla&veh=sem&adid=22222222227014431015&wl0=&wl1=g&wl2=&wl3=13698474550&wl4=&wl5=pla&veh=sem

In stock and ready to ship. Hope its ok to post links like this ...

Scott

Plus, if your credit card uses thank you rewards, you can put them toward a walmart gift card toward it. Cha ching.

What's the difference between EP4000 and EPX4000 other than the looks?
Amazon sells EP4K version for $275 too. EPX4K is $399.

The EPX has a switching type power supply and is lighter. Overall should be identical.

Get a used one from Guitar Center for < $200

No crap? How do you do that? Online or the brick and mortar stores?

Don't forget unit-unit variance.

Big differences in Qes are more likely than not, I expect, traceable to different-strength magnets. That "production" ones would have weaker magnets (higher Qes) than "prototype" ones is fairly predictable. That seems to happen with a lot of buildhouses, alas.

If one really cares about the "alignment" of a closed box (I used to, but have basically been convinced by experience that it's irrelevant unless incredibly off) then there's no substitute for individualized measurement. And for more complicated alignments, obviously one should measure the actual drivers one intends to use.

Online. Search the 'Used Gear' section for EP2500 or EP4000. These used units pop up all the time. I got an EP2500 last year for under $200 shipped. Still working great.

Here's a used EP2500 for $150.

http://www.guitarcenter.com/In-Store-Used-USED-EP2500-108181271-i2724346.gc

Nice! Big is awesome. You are in good hands for sure.

Having to book him 8 months in advance sounds about right...

The response on foam gaskets is much appreciated.

I saw the 18" is safe in a down-firing enclosure and plan to go that route. How far should it be from the floor? Is there something in the T/S that help determine what would be most effective? I've read 3-4 inches but couldn't find any reasons other than not slamming your driver into the ground. The surround still sticks out ~3/4" past my double-baffle, so I'm not sure where to measure distance from the floor from. Hope this makes sense.

Would love to hear your thoughts...

Have a look at this [expand the FAQ at the bottom].

If you go by this, you're probably quite safe with 5 inches. The effective cone area has a diameter of 15.25 inches if you want to do the math proposed on the site.

Yes, but simple programs like WinISD don't reveal it. Trial and error while measuring response is the best method.

The differences are not limited to Qes and are too big to be attributed to unit-to-unit variance IMHO.
It is going to be bass-reflex boxes in my case, wrong model can easily result in suboptimal performance and blown drivers . I wish we could get some certainty about the specs before we finalize the plans.

I disagree. Cones with varying mass, magnets of varying strength, gap tolerance, etc. are all going to lead to such differences.

The only way to get any kind of "certainty" about driver parameters is to measure the actual devices you plan to use, perhaps a couple different times on different days, and average the measurements.

Also, I would recommend using closed boxes instead. Vented boxes with low tunings are usually problematic-sounding, due to the high level of the vent resonances. If you're planning to use PR's, that's a different (and better) situation.

Recently I was told by a higher up in a very large, very reputable speaker manufacturer that their acceptable unit to unit tolerance was +/-15%. He then went on to say that there is variation from batch to batch and that most were well within that range. This is straight from one of the most advanced driver mfg's in the world. With these small boutique operations I would expect similar variation or worse. I have had drivers measured on the same day back to back that were quite different.

Additionally you have things like the temperature of the suspension, motor and voice coil which can shift things drastically. The prototype that I had exhibited perhaps the highest compliance suspension I have seen. Fs was around 14Hz and the moving assembly is not that heavy. It was WELL broken in to say the least. All things equal a looser suspension lowers qes/qts
Edited by Ricci - 1/24/13 at 8:59am

Thank you for chiming in, Josh.
What parameters were they talking about? The difference between your measurements and the SI specs is over 100% for Qms and over 30% - for total Q.

In these instances would you feel it might be prudent to have WT3 or DATS and build based on those numbers after the suspension has broken in? Thanks.

We have been busy working, shipping out drivers, responding to emails as best we can, etc. And I edited the web page a few minutes ago.


Josh summed it up quite well. Differences in test equipment used, temperature, humidity, etc, all lead to varying results. T/S measurements are very finicky on their own - if you sneeze in the room while they're being taken the results will be different. Klippel is even worse (but that's a good thing).

Thank you, Nick

Would you say that production units are more likely to be close to your (Klippel?) numbers? Fs 17Hz, Qts 0.38,etc.

Thank youj

Would two of these sealed in a 4 cu ft box each be enough for a 20x15x10 room thats open to another small 10x10x14 room? I sold my two sealed dayton HFs, so I'm out of sub woofers and need two sealed or ported does not matter.
Edited by deathinc - 1/24/13 at 11:46am

epx also has RCA in's and the lights are cooler.


Very Nice!! I have had the chance to meet Shane and buy off some of his overstock Super great guy! You will get some awesome design advice for sure!! Glad you are still around!

For those interested in how these will do in an LLT alignment, in about 6 weeks (hopefully less), we'll know! I just ordered two HT18 D4s which I'll be putting in a couple 650l (~23cu ft) sonotubes tuned to 12Hz. Once my tax return comes in, I'll start buying everything else I need. The drivers I bought now because there were not that many left, and I didn't want to get sniped by somebody else here and have to wait for the next batch of drivers. (in which case I probably would have gone with the XCON18s)

My planning thead: 2 18" LLT Sonotubes: Preliminary Planning

The high speed is always so cool

niiice

what camera was it shot with?

High speed stuff was a canon S100 at 240 fps. I'm sure there are some that do it with higher resolution, I know the go pro 3 black edition can do 240 fps at a better resolution.

In that specific case it was BL. Try changing the BL +/- 15% and see what happens to the rest of the parameters. Again that's totally disregarding the suspension and MMS variations. Turns out that the particular driver that started that conversation apparently had a motor not fully charged because the next one was what I consider to be dead on.

If I run tests on a driver back to back they will be slightly different every time. Now if I do it 2 weeks apart they will be a much larger variation for the same exact driver. All I can say is that is what I measured from the proto driver on that day. I trust the Klippel results for that driver on that day as well. If you absolutely have to know to the nth degree you will have to measure your own drivers and go from there. Sealed enclosures are very forgiving amd it's not worth troubling yourself over. Vented is a little more finicky but it's not like the design will be trashed by some variations even large ones. Not to mention all of those small signal parameters go out the window anyway once real power is applied and excursion gets high.

I never get tired of watching excursion testing.