Flex Your PCD Mettle:

[HeartFixr]

Re: Need help with crossover

Jumping in with both feet, actually I'm all in and trying to build the Econowave Altec GPA 414-8B with QSC waveguide and BMS 4552 compression drivers. In looking at Zilch's picture he had a 3/4" baffle with the waveguide front mounted and the Altec rear mounted. If I use a 1 1/2" front baffle and rear mount the Altec, it will reduce offset z measurement. How big of a deal is this with the crossover and if so, how do I compensate for it?
BTW, is this speaker ported (which is what I am building)?

[dtruck]

Re: Need help with crossover

If you move the woofer back another 18mm, you'll lower the forward lobe angle about 3-4°. Not generally a big deal but from what I can see, that particular combo was designed with the lobe 0° straight out from the midpoint between drivers, and you want to error on the side of higher than 0°, not lower. It would be much better to front/flush-mount the woofer, but I think that's not an option with the Altec? I can't recall if the frame gets in the way. If flush mount is not an option, you'd really want to stick with 18mm for the front baffle or router out an 18mm recess in the back for it to sink into, I'd say.

[HeartFixr]

Re: Need help with crossover

Wow, thanks for your brilliant input. The Altec can be mounted either way and can definitely be mounted front/flush and would actually be easier.
Back to the actual drawing board before I start butchering my wood/MDF.

[robertm]

Re: Need help with crossover

I vaguely remember some talk about how good the woofers were from the Criterion 100B, placed in 4 ft3 boxes, going down to 35 Hz or so. Any reason why this would be a good approach as an econowave worth giving a shot? My system currently has large advent woofers in a 1.1 ft3 box, wonder if it would be a significant step up to go with these old woofs.

[NEO Dan]

Re: Need help with crossover

If you want great sound and don't have the inclination to measure and engineer the crossover there are several pre-engineered winners listed already in the beginning of the thread, also a search for SEOS should yield DIY kit options if that's what turns your crank...

[HeartFixr]

Re: Need help with crossover

I have almost finished the Econowave Altec 4148B with BMS4552 and QSC waveguide. I have used the crossover schematic designed by Zilch and friends and have this incredibly stupid question. Does it make a difference which end of the inductor or capacitor is wired? Are they polar? I have some iron core inductors and others are wire wound. How am I supposed to tell which lead goes where in the circuit? None of the leads on the inductors or capacitors were labeled as positive or negative.

[NEO Dan]

Re: Need help with crossover

Go for it HeartFixr crossover parts are generally non-polar devices or bi-polar in the case of electrolytic caps. It's the layout that makes the "magic" happen... Sounds like you'll have quite the speaker there, congrats

[killa]

Re: Need help with crossover

+1 This is a AC circuit so there is no pos or neg so to speak. Current flows both direction.

[Pete Schumacher]

Re: Need help with crossover

318,000 views on this thread . . . who says one guy can't make a difference?

We miss you Zilch.

[Gary Lightfoot]

Re: Need help with crossover

Hi Pete, nicely said.

318,000 views on this thread . . . who says one guy can't make a difference?

We miss you Zilch.

I can't remember how I stumbled across the econowave threads, but I've been reading as much as I can on all of them all over the place for a few weeks now. I want to make some LCR waveguide speakers for my small home theatre, and I was getting a real feel for Zilch with his enthusiasm and knowledge (most of this stuff is way above my head), so I can't tell you how gutted and choked I am to find he passed away well over a year ago :(

Amazing how you can feel about someone you've never met even when they've been gone such a long time....


Well, my main reason for posting is that I have some 8" QTX PA speakers that I think are ripe for an econowave retrofit, but I've a long way to go. They have 8" woofers that ideally need to be measured (probably replaced), but as for the CD. here in the UK it's difficult to get the Seleniums at decent prices, so I'm looking at the DE10 with either the Pyle PH612 waveguide, or perhaps the ME10 (assuming the woofer goes high enough for a 2.5khz crossover). PH612 can be made to fit but is it too big for use with an 8" woofer? Is the ME10 considered a reasonable candidate for econowave use?

The 18Sound XT120 horn looks ideal size wise, but again comparatively expensive which brings me back to the 612 at only £9.99 ($15) inc del here in the UK.

There are some PA Audio CDs and waveguides that look like they have potential, but Earl Geddes says they don't measure as well as advertised when he's had them to play with. The PA-DE34 looks ideal (cost and frequency plot wise), but as with the QTX woofer, they need to be measured (this is something I think I need to learn and do myself). If anyone here has any experience of them I would be grateful for your input. It might be worth a punt just to see at the price.....

Any ideas on the suitability or experience of the PA-Audio PH-170 horn? It looks a little like the XT120 so again, wondered if anyone had tried it.

Thanks in advance guys

Gary

[buzzforb]

Re: Need help with crossover

First time poster and first time builder. Amps and FR speakers have been my game up to this point. I am about to attempt a version of the econowave that I want to look ad perform similarly to the JBL 4429. Based on sims I have done, the TD12s in a 2.5^ft box, tuned to between 30-32Hz can get plenty low with a nice smooth rolloff. My concern has to do with issues that would arrise as a result of the efficiency gap between the compression driver and woofer. I plan on using either the Denovo 360 or DE250 and will try either QSC or PYLE PH 714. If it works ou as expected, I may move up to 1.4" on custom wood horn. I am just unsure of power response issues with driver mismatch. I have mini DSP and DIy active crossover. Figured I would try that first before passive solution.

[Pete Schumacher]

Re: Need help with crossover

There's no issue with sensitivity mismatch, as that is handled in the crossover with padding on the tweeter. Almost every econowave variant has a woofer with much lower sensitivity than the compression drivers.

[buzzforb]

Re: Need help with crossover

What are the general impressions of the AE woofers. Although they seem superior on paper, you don't hear a lot about their sound. I also have 416-8a and 414-8 to work with, but they require much larger boxes. These are more well known for their sound, although it can get a little cultish. What would be the ideal AE driver for this combo?

BTW, WinIsd shows that the TD12s in 3^ft box tuned to 35Hz will go as low with similar slope as 416-8a in 9^ft and td15m in 6.5^ft box. Only downside is 6dB less sensitivity. I would assume that it has enough linear travel to handle much higher SPL's. It really does seem to be a question of box size and sensitivity. On another forum, there are those who would suggest that a speaker built for power wants to be turned up to sound good. THis is my main concern.

[Pete Schumacher]

Re: Need help with crossover

What are the general impressions of the AE woofers. Although they seem superior on paper, you don't hear a lot about their sound. I also have 416-8a and 414-8 to work with, but they require much larger boxes. These are more well known for their sound, although it can get a little cultish. What would be the ideal AE driver for this combo?

BTW, WinIsd shows that the TD12s in 3^ft box tuned to 35Hz will go as low with similar slope as 416-8a in 9^ft and td15m in 6.5^ft box. Only downside is 6dB less sensitivity. I would assume that it has enough linear travel to handle much higher SPL's. It really does seem to be a question of box size and sensitivity. On another forum, there are those who would suggest that a speaker built for power wants to be turned up to sound good. THis is my main concern.

The AE woofers are among the very best on the planet. I've never heard bass as clean, clear, defined, as I have with those woofers.

We use the TD15H and the TD10M in a couple of our builds. The TD15H is a woofer in a 3-way tower that we cross at 400Hz. The 10M is used in a 2-way crossed at 1100Hz to a Beyma TPL-150H AMT. The TD10M is a pretty remarkable 10" woofer that does a great job over its range. Objectively, they have incredibly low distortion, and subjectively, their sound is smooth, natural, with plenty of resolution to satisfy almost anyone. At lower volumes, some of our other models deliver (subjectively) superior midrange clarity and resolution, but when the volume is cranked, the effortless ease exhibited by the AE woofers is readily apparent.

Econowaves in general are designed to be turned up, since they use pro drivers for the most part and are able to handle the power. However, they also have higher than average sensitivity which means you don't need a lot of power to get them playing pretty loud. What these woofers are able to do is deliver dynamics, uncompressed. That brings a lively quality to the music regardless the average SPL.

And this is purely my opinion here. The compression tweeter will always be the weak link any econowave build using AE woofers.

[buzzforb]

Re: Need help with crossover

ThAnk you for the very clear and concise answer. I think I will go for the 12s. Do you get similar numbers modeling the td12s? I know we are talking posted numbers here.