Great reading.... The legend of El-Pipo

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Hey "Hempacoustics" and "El-Pipo" seem to have a connection other than loudspeaker components? :)
This really may be a marriage made in heaven!
I spoke at length with Perry from Hempacoustics. Very interesting and informative. The current 25 Tsuzureko is a custom built product with lots of expensive components,including a Honeywell fabric called "Spectra 1000" for the spyder. He indicates a fairly high percentage do not meet final North American quality control . Adding to the overall cost.
Around $1500 retail.
He is building a new prototype in North America. Quality control would be better and no shipping back and forth to China etc. Might be less expensive as well.
Someone from Nelson Pass's group ordered a couple of the current models.This may be tough to beat. Albeit relatively expensive
 
Drivers...

Plan: Reproduce an accurate copy of the original el pipo...

Today I purchased a 24" x 12' length of Sonotube as well as MDF for a baffle/baffle-box. I followed Nelson's reference to MCM Electronics for the purchase of the drivers, but they have been discontinued! I called MCM to see if they could provide other sources or theile/small parameters, but no luck. Has anyone done this with other drivers?

Choosing drivers:

My understanding of transmission-line-driver-pairing is as follows:
1) Ideal Qts of driver between 0.45 and 0.50...
2) High BL (Motor Strength)
3) Low Driver Fs

Has anyone had this experience? Different opinions?
 
Baby el pipe-o.s

Built the smaller ones Nelson Pass mentioned in the article using 6' sections of 8" Sonotube with the Tang Band w8-740p's. WO00W! Bass is clean and DEEEEEP. Used ~2.5 lbs of Acusta Stuff per side and driving with ~200 wpc. Using Reckhorn xover and just dialed in to taste . Have Tru RTA,but too busy listening to music to tune! Great cheap bass!!!!!!!!

All Hail NP!

Will post Pictures as soon as stop listening long enough to post
 
http://www.pyleaudio.com/itemdetail...Audio&cat2=Replacement Woofers&model=PDW21250

(Pay no attention to the price on their site, it goes for much cheaper than that!)...

I've been very interested in this woofer as a cheap cost effective solution for various potential projects for quite a while now. Only thing holding me back from trying one is the obvious lack of information. I've emailed them several times over the last several months for some kind of update or any information regarding T/S parameters they could possibly give me, only to receive no response whatsoever. Wouldn't surprise me if they didn't even understand my question, lol. Sad, sad, sad. I mean, I know it's Pyle etc.. but c'mon!

Anyway, I've seen quite a few people selling it on eBay for months now in the $150 range and less. It's on a few other sites as well for a bit more. I even noticed recently that MCM has it now too.

If anyone with a Dayton WT3 or similar would be willing to give it a shot, I'd be SOOOO grateful, regardless of the outcome.. as long as we get some specs at least. I've got too much stuff to sell in the meantime.. lost WAY too much from taking risks of all different sorts over the last few years, among other things.

I just thought to post it here since it might turn out to be a good candidate for such a project.

Also, I'd be interested in a response to tylersphile's question a few posts up, as well as any other recommended source of info for these relatively simple TL designs.
 
Also, I'd be interested in a response to tylersphile's question a few posts up, as well as any other recommended source of info for these relatively simple TL designs.

This is not a direct answer really but...

I wouldn't build anything without modelling it first. Regardless of guidelines or rules of thumb. Especially when it's so EASY and FREE.

Basically these are just straight (not positive or negative taper) end loaded transmission lines. The TL modelling software that comes bundled with the old DOSBOX program does a reasonable job at modelling these. (BUT it's not as super accurate as other software AND I don't really trust it to calculate stuffing). Or you can get some really decent software that is not free.

Try it out and you will find out pretty quickly why I don't like straight tl's. Response is super ragged, especially when the driver is end loaded. Requires LOTS of stuffing to get a somewhat flat response. A more refined line layout with optimal driver positioning yeilds a far better shot at flat response with minimal stuffing.

OTOH, a sonotube pipe with a driver in one end is by far the fastest and easiest way to make a lot of noise.
 
just a guy said:
Try it out and you will find out pretty quickly why I don't like straight tl's. Response is super ragged, especially when the driver is end loaded. Requires LOTS of stuffing to get a somewhat flat response. A more refined line layout with optimal driver positioning yeilds a far better shot at flat response with minimal stuffing.

I was just starting to notice this while playing around with one of MJK's MathCad worksheets as I saw your post. :(
On the positive side, thanks for confirming my observations so quickly. ;)
 
Since you have the good software anyway, try adding a slight (positive OR negative) taper to the line, keeping ~ the same overall enclosure volume, and move the driver to about 40% of the way down the line. That should provide MUCH smoother response, requiring MUCH less stuffing. Unfortunately it's no longer as easy to build as sticking the driver in the end of a length of sonotube.
 
Re: Drivers...

tylersphile said:

I followed Nelson's reference to MCM Electronics for the purchase of the drivers, but they have been discontinued! I called MCM to see if they could provide other sources or theile/small parameters, but no luck. Has anyone done this with other drivers?

Hmm, Google returned this in its typically tiny fraction of a second: http://www.evilserv.com/forum/?id=1068&from=10

GM
 
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