Flex Your PCD Mettle:

[NEO Dan]

Re: Flex Your PCD Mettle:

I probably over-stated some. The Aurasound FR curve looks pretty much like the Dayton DC300, which I have used in an Ewave and is surprisingly good. This with the original standard XO rather than the new one that was more optimized for the DC300 in the Dayton Trap Cabs.

The Aura driver suggestion was not aimed at you in any way, you have HT screen channels, no need for deep bass extension.

It's kind of ironic that the EWave started as a modular approach to repurpose old cabs and woofers for good sound at smallish dollars. Looking at where we are at now seems to prove Voltaire right: "the better is the enemy of the good". "Course that's pretty much the Hi-Fi story.

The original e-wave concept is IMO the ultimate upgrade for those thrift shop cabinets, and most commercial speakers for that matter.

Your build on the other hand has the potential to go beyond that. Currently the D220ti is holding you back noticeably, the PA310-8 is OK but the response to 3k is actually a byproduct of cone breakup. The demodulation rings molded into the cone spread out the breakup, so instead of a single spike you you get "extended response", arguably the single peak is easier to deal with because you can put a notch filter on it, but if either situation happens within the desired band of operation your gonna hear it - just like you hear the broad band breakup in the d220ti. The breakup of both drivers is typical of their respective designs, a pick your poison and work with it type of situation. In favor of the PA310-8 though is the copper in the motor and the current price is pretty nice, that and the fact that you already have it kinda seals the deal ;)

[Zilch]

Re: Flex Your PCD Mettle:

SR is crossed at 1.6 kHz.

The 8" square waveguide is available in both 90° and 120° x 50°; I crossed it at 1.6 kHz in Spitwad and 1.5 kHz in AR4x. Review the project summaries from the first post of this thread. Get there by hitting "First" at the top or bottom of any page herein.

For details where JBL crosses them:

http://www.jblproservice.com/navigation/AE%20Series%20Compact%20Models.htm

[vlad335]

Re: Flex Your PCD Mettle:

SR is crossed at 1.6 kHz.

The 8" square waveguide is available in both 90° and 120° x 50°; I crossed it at 1.6 kHz in Spitwad and 1.5 kHz in AR4x. Review the project summaries from the first post of this thread. Get there by hitting "First" at the top or bottom of any page herein.

For details where JBL crosses them:

http://www.jblproservice.com/navigat...t%20Models.htm

Cool. thanks Zilch!

[BassMe]

Re: Flex Your PCD Mettle:

Summarizing the discussion found here: http://techtalk.parts-express.com/sh...d.php?t=220964

I am looking for a rockin set of towers for playing music very loudly and clearly. Need good bass extension into mid to low 30's so that these speakers can act stand alone for music reproduction in parties or at home. They will eventually be paired with a sub for HT use.

After discussion with Zilch and a number of others I have moved away from a Magna *** Laude Build and am focusing my attention on an Econowave Build.

My Budget is approximately $500 for all speaker parts not including MDF or Shipping.

Zilch has proposed a Econo SR with dual woofers. The purpose of my posting here is to consolidate knowledge and ask for help from those far more knowledgeable about speaker design then myself.

The goal:

A Econowave SR with dual woofer build.
Maintain high SPL while extending F3 into the mid to low 30's.
Maintain an easy to drive impendance so that these speakers can be run from any old amp.

**Note: I know essentially nothing about Xover design or electrical networks**

Zilch mentioned a 2.5way, though I am curious about maintaining a 2 way design with the woofer's Xover being wired in series while the woofer themselves being wired parallel to maintain an 8ohm impedance. (this is how the magna *** laude is wired, I'm not sure if it would be applicable here?)

Cabinet size is a non issue. I happy with anything up to 1.5m x .5m front baffle.

So if anyone can help with crossover design suggestions and/or cabinet configurations please feel free to chime in. I know it's asking a lot, but I am trying to learn at the same time as I do this so I can help out. If there is anything I can do please let me know.

All the Best.

[Zilch]

Re: Flex Your PCD Mettle:

The "0.5" alignment maintains the 8-Ohm impedance down to some low frequency (~200 Hz) where the second woofer cuts in, dropping the nominal impedance in half. This is accomplished with an inductor of the appropriate value in series with the "helper" woofer. The lowered impedance contributes to the augmentation by drawing more current from the amp at low frequencies, in addition to the doubled cone area and mutual coupling. Only the one woofer plays the midrange frequencies, so the two woofers do not interfere with one another in this region.

Here are a couple of JBL examples:

L1 - http://www.jblproservice.com/pdf/Cab...ries/4612B.pdf

L101 - http://www.jblproservice.com/pdf/Stu...ies/4435LR.pdf

Bonus - you find the inductor:

http://manuals.harman.com/JBL/HOM/Technical%20Sheet/Everest%20DD66000%20ts.pdf

I don't know how well it'll work with dual PA-310-8s, or what the optimum tuning of that alignment might be; perhaps someone here could model it....

[BassMe]

Re: Flex Your PCD Mettle:

Ok so, after finding reading a few more things about cross over design and keeping a electronic symbols guide open on my 2nd monitor I have fairly worked out what I am seeing in the first two diagrams, the third one?? I am thoroughly lost lol. Seeing as I don't understand fully understand the inductance numbers presented by the inductors and how this correlates to Hz crossover points I am still a bit lost. But I can understand the concept of 0.5 system a lot better now.

Even discounting the third one there is some fairly complex work going on in those xovers (at least to my new eyes).

Anyways, modeling two of the PA-310-8's and modeling two of the DC300-8's from the standard would probably be wise. Just for comparison I guess.

I will read up a bit more about modeling and crossover design and see if I can work some of this stuff out myself. I have used the simple woofer box modelers available on web pages, but of course these don't take into account dual woofers and crossovers.

[Zilch]

Re: Flex Your PCD Mettle:

Yes, dig in and figure this out. You'll wonder if the helper woofer is even playing when you build it.

['Til the bass hits...! :p]

Watch Skywave's video of a pair of 16-Ohm Altec 414Z in action here:

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

Conceptually, you just augment the standard design with a second woofer and an inductor in series with it, the combination connected in parallel with the main woofer. Go to the Crossover Component Selection Guide in the Parts Express catalog or on the website and look at the Low Pass 6 dB/octave list of inductors versus frequency. As example, for an 8-Ohm woofer at 150 Hz, it's an 8.49 mH inductor, and at 200 Hz, 6.37 mH. How about #266-576 at 8 mH for under $12? Looks like #266-580 will do it ~125 Hz for 50 cents more....

[BassMe]

Re: Flex Your PCD Mettle:

Ok so I'm looking for a modeling program that lets me set the helper woofer to cross in at 200 or 150 Hz. WinISD doesn't. On WinISD the PA-310 doesn't model well into mid 30 tuning well at all, but that doesn't include the inductor. The DC300's on the other hand rip right down into 28Hz... in a 300L cab lol.

I'll continue on.

Thank you for the help Zilch.

Do you think I will need to investigate the difference in cross over due to a different front baffle?

[Mayhem13]

Re: Flex Your PCD Mettle:

What WinISD and Unibox don't take into account is baffle step losses, which depending on the cabinet dimensions and the speakers placement in the room can be as much as 6db from 800hz on down. Primarily the .5 woofer serves the purpose of combating baffle losses as well as cleaning up the midrange a bit. You're right about the 310 and it's extension, so why force it down that low.....even with two in a .5 config. Just be happy with the beauty of what the 310 is, a great midwoofer at an excellent price hence enjoying the value of ultra low HD in the critical midrange.........and 95db eff. too!;) As a two way, the SR compact clearly needs a stand of somesorts so take those extra $$$ from the .5 woofers and inductors and build some bass bin,sub stands. The Tuba or other tapped horns would be perfect for this application as they're hugely Econo on price yet produce prodigeuos amounts of clean LF output.

[BassMe]

Re: Flex Your PCD Mettle:

So your recommending a stand that is a sub? If you could provide a link to "The Tuba or other tapped horns" I might be able to have a look. I'm not sure what these are.

I don't think the PA-310's will be usable as you have said. I have modeled the PA-310 by itself and cannot get a F3 down near 35Hz at all. Even with two I don't think it would work. If only I could figure out how to model with one of the woofers cutting in at 200Hz and down. Neither WinISD or Unibox seem to support this. I might just not be recognizing it though. I won't give up on this till I figure out how to model this situation. The extra output from 150-200HZ down would have to make a difference.

The extra cost for sub amp plates and drivers wouldn't equal the cost a 2 extra woofers though :(.

Would just using 2 DC300's topped by a econo horn for highs work? The extra woofer would *i think* obviously help output significantly more volume and using the LPad you would just match the highs to this. I donno if this is completely ridiculous, but my special brand of logic dictates that 2 speakers playing the same stuff would have to be louder then 1 speaker giving you an overall gain in SPL while straining neither speaker as hard for bass extension providing crisper sound? I really do want to keep the system as 2 mains that rock not 2 mains with some subs that rock. Makes it easier to take to my friends houses and break their windows.

Anyways I'm off to bed, all the best everyone, enjoy your Sunday to those just getting started.

[Mayhem13]

Re: Flex Your PCD Mettle:

There's always a catch or ' no free lunch' as some might say.:p

Bill Fitz will chime in here on the benefits of his horn subs. I'll let the master share his thoughts.:D

On a side note....these are BIG subs.....and rightfully so to get that kind of output on a budget.

[BassMe]

Re: Flex Your PCD Mettle:

Well bill's tuba's sure look interesting. An econo sr sittin on top of a tuba would sure make some noise. Then have a 2nd set. You could technically integrate the separate cabinets into a single cab? Now I'm really going to bed. Thinking about running ridiculously loud speakers.... This is bad for my wallet I can feel it already.

Peace

Edit: been looking over bills website. This little thing is insane http://www.billfitzmaurice.com/autotuba.html 2 of these running with 70 watt sub plates with 2 econo sr's sitting on top would pump a house party.

[Mayhem13]

Re: Flex Your PCD Mettle:

The autotuba relies on cabin gain in a small space....which you won't have.;) If this is for HT, you need to explore options for solid extension to 20hz....Otherwise you'll miss the good stuff!:D You don't NEED to go the route of Bill's output monsters, but they're pretty much the value leaders IF you have the space......and space you'll need for a pair of THTs.:eek:

Consider dual conventional 15" drivers in ported cabs as well. A bit more pricey BUT a bit smaller and easier to build as well. Cross the SR at 100hz over a pair and you'll have a stellar midrange as well as authoritative, clean bass to the teens.

[BassMe]

Re: Flex Your PCD Mettle:

Space isn't really an issue. This is all sounding very positive. I'll have to have a post on their forums and see what way I want to go.

Thanks mayhem

[Russellc]

Re: Flex Your PCD Mettle:

Zilch, Pete, or anyone who can help, I've obtained a laptop, microphone, still shopping for the pre/phantom power(likely will be the one Zilch showed here or the M Audio mobil pre) but have loaded PCD and am wanting to figure it out.

Looking at the "Flex your PCD Mettle" I thought I would begin with the projects mentioned there, as the FRD, ZMA and so forth files are already there, and it seems like a good way to get used to this software in the beginning. I assume I can load in those files and hopefully replicate the results.

I have also loaded in the FRD consortium stuff for when the time comes to generate my own files.

When looking at the various files in the thread provided by Zilch and Pete, I've noticed some open differently than others. For example, the files in post #5 (FRD) open just fine, showing three lines of numbers. Others, like the files in posts #22, #25, or #108, open, showing files of the drivers, but they will not open revealing the three lines of info.

My preliminary questions are, whats up with the files that dont fully open (I'm sure that's how they are meant to be) and secondly, how can I insert these files into PCD to hopefully replicate Zilch and Pete's results?

I would seriously appreciate any help with this, it isnt being to intuitive for this old fart.

Thanking in advance,

Russellc