Flex Your PCD Mettle:

[Flacjunky]

Re: Flex Your PCD Mettle:

1.5 mH/18 uF is a modest lowpass. The parallel notch filter, R4||C4||L3 is primarily mitigating a peak in the woofer response between 400 and 800 Hz, but that might be considered BSC, even though it's not shelving. If you're finding they are too "warm" sounding once your subs are running, then you might try bypassing that, meaning shorting that parallel combination. It that's then too "forward," send Pete a PM and ask him to jump in here with a recommendation.

Is your cab split into two chambers up there? If so, what is the volume of each? (

Right now, I dont have any negative issues with their performance, I was just wondering how that baffle step compensation might be affecting my sound in unintended ways due to me being wall mounted.

While the Woofers dont sound as good as I expected them to when the L-Pad to the HF is turned completely off, the overall unit sounds great once the HF is doing its thing.

I was expecting the PA310, by itself, to be as vibrant as the old Eminence guitar speaker that I run full-range (With a Horn Tweeter) out on the deck ..... and its not. The PA310 sounds relatively cloudy by itself.

But yes, the total cabinet is divided into 3 chambers, with each Main having about 7.5 gross CF. Which I realize is probably too big to run the PA310 sealed like I'm doing. So thats probably a bigger detriment than the BSC.

But for now, and perhaps the rest of my life, it'll work just fine like it is. As a unit, it sounds really good to me.

Maybe someday I'll measure the response, and see whats really going on.

Flacjunky,
I know you have a narrow room and no toe in, but have you tried tweeters to the outside

Well, the logic behind my driver placement, was that I, like most aging Flacjunkies, have some HF hearing loss. But in my case its worse in one ear than the other. And the further apart the HF sources are the more obvious and distracting the unbalance is.

So by putting the HF sources as close to the center as possible I was expecting to mitigate some of that imbalance. And right now I'd have to say its working as planned. When I turn my head side to side in front of the speakers I dont notice any differences in volume, whereas with my old setup (tweeters further apart) I do.

[Zilch]

Re: Flex Your PCD Mettle:

While the Woofers dont sound as good as I expected them to when the L-Pad to the HF is turned completely off, the overall unit sounds great once the HF is doing its thing.

I was expecting the PA310, by itself, to be as vibrant as the old Eminence guitar speaker that I run full-range (With a Horn Tweeter) out on the deck ..... and its not. The PA310 sounds relatively cloudy by itself.

With the lowpass still in place, you're not hearing the woofers full range. I never tried that, either, other than the MLS measurement to get the raw data, not program. They are certainly beastly heavy woofers.

But for now, and perhaps the rest of my life, it'll work just fine like it is. As a unit, it sounds really good to me.

I can't tell you how gratifying it is to see a system like yours come together. There are now over 100 "registered" EconoWave builds, and every one of them is different. That was our intent from the very outset, and there is great pleasure in witnessing the vision fulfilled by DIYers around the world:

If this is what entry level honk and nulls sound like ...... I'm diggin' it. :D

[Skywave-Rider]

Re: Flex Your PCD Mettle:

Well, the logic behind my driver placement, was that I, like most aging Flacjunkies, have some HF hearing loss. But in my case its worse in one ear than the other. And the further apart the HF sources are the more obvious and distracting the unbalance is.

So by putting the HF sources as close to the center as possible I was expecting to mitigate some of that imbalance. And right now I'd have to say its working as planned. When I turn my head side to side in front of the speakers I dont notice any differences in volume, whereas with my old setup (tweeters further apart) I do.

That makes a lot of sense. A lot of people run monitors esp. nearfields in that configuration. Nice job on the boxes, too.

[Zilch]

Flex It Round #7.0 - EconoWave Altec

Vintage Altec 414Z woofer with BMS 4555 re-entrant ring radiating compression driver on JBL 1.5" PT-F95HF progressive transition waveguide:




In Dayton KD trapezoidal cab kit:



[Nice focus, Zilchster.... :p ]


414Z is nominal 16 ohms, and as shown above, rear-mount only. New units in either 8 or 16 ohms may be available from GPA, though they are not listed on their website. Inquire:

http://www.greatplainsaudio.com/

JBL manufactured high-frequency ring radiators for nearly half a century before BMS perfected their clever re-entrant design concept, and expanded it into general-purpose compression driver applications:

http://www.bmspro.com/

The response/performance characteristics of the 1" and 1.5" exit variants of the 1.75" diaphragm models 4550 and 4555 are very similar. There is also a nifty 1" throat Nd version, 4552ND. Mate them with XT1086 or QSC waveguides and flex your mettle.

Also, 4540ND, a diminutive tweeter driver, thread-on, mates well with smaller waveguides....

[Skywave-Rider]

Re: Flex Your PCD Mettle:

Cool!

[Zilch]

Re: Flex Your PCD Mettle:

Cool!

Says Skywave, who coincidentally has 4ea. vintage Altec 414Z woofers, BMS drivers, and KDT cabs.... ;)

[Zilch]

Re: Flex Your PCD Mettle:

First attempt; the forward axis is WAY high, tho:

[Zilch]

The Files

C/c = 10.5", LF piston = 10", HF throat = 1.5", measuring distance = 44", measured midway between woofer and waveguide, phase = minimum, L-pad @1:00 included:

[Skywave-Rider]

Re: Flex Your PCD Mettle:

First attempt; the forward axis is WAY high, tho:

That is amazing.

[Skywave-Rider]

Re: Flex Your PCD Mettle:

Zilch, the BMS 4555 exhibits no uhf peak?

I plan to take home one of my 414s tomorrow night and play around with QSC and BMS 4552ND on top of trap cab.

[Zilch]

Re: Flex Your PCD Mettle:

Zilch, the BMS 4555 exhibits no uhf peak?

It's there, big time. I've notched it out: 0.68uF, 3.3 Ohms, 0.1mH.

Gonna need help with this one, looks like; I can get the HF flat as Kansas easily, but I'm struggling with the forward axis when mated with the LF.

A single 414Z needs a sub, but I wouldn't be above installing a second pair in KDTs as stands and running them 2.5 mode. At this point, I have no clue what the optimum tuning for that combo might be; you have more experience with that part:

http://www.youtube.com/watch?v=97CEcUEjJAE

I plan to take home one of my 414s tomorrow night and play around with QSC and BMS 4552ND on top of trap cab.

[We'll want pics, of course.... ]

[Mayhem13]

Re: Flex Your PCD Mettle:

Top end and reverse null look fantastic! The response from 1-2khz is as smooth as ANY high end system i've ever seen a measurment of. IMO, that range is where it's all about. Don't know much about some of the vintage cones you guys are workin' with though.

[Zilch]

Re: Flex Your PCD Mettle:

Top end and reverse null look fantastic! The response from 1-2khz is as smooth as ANY high end system i've ever seen a measurment of. IMO, that range is where it's all about. Don't know much about some of the vintage cones you guys are workin' with though.

That null runs 20dB deeper than shown, actually, clear down to the ZilchLab noise floor.... :D

[ARSIS]

Re: Flex Your PCD Mettle:

wow... you guys really put in some work with this speaker design. can someone help me build one? my budget is $800 excluding enclosure materials. i wanna go passive. i want to build three for ht. i listen to mostly heavy metal amd war theme orchestra. i never built crossovers or hifi speakers. i've built a lot of subs for car audio... never for home audio.

[Zilch]

Re: Flex Your PCD Mettle:

wow... you guys really put in some work with this speaker design. can someone help me build one? my budget is $800 excluding enclosure materials. i wanna go passive. i want to build three for ht. i listen to mostly heavy metal amd war theme orchestra. i never built crossovers or hifi speakers. i've built a lot of subs for car audio... never for home audio.

The cost matrix is in the first post of this thread, along with links to each of the dozen variants shown there:

http://techtalk.parts-express.com/showthread.php?t=215536

This is FUN stuff; over 100 DIYers have "registered" their EconoWave projects, and many times that have been built worldwide....

http://audiokarma.org/forums/showthread.php?p=2260584#post2260584