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Zilch's AK Design Collaborative - Econowave Speaker

Explain

Can you explain, same signal to both drivers??

When would it not? Because of low quality crossover, or another component in the mix?


http://www.behringer.com/CX2310/index.cfm?lang=ENG

Like the CX3400, the CX2310 offers absolute precision, state-of-the-art circuitry, professional components, ultra low-noise op amps, fully balanced in and outputs and intuitive operation. In addition to full-fledged 2-way stereo/3-way mono operation, the CX2310 features a separately adjustable subwoofer output, giving you an extra low-frequency band

Features
24 dB/octave, state-variable Linkwitz-Riley filters for precise frequency separation

Absolutely flat summed amplitude response, zero phase difference

Individual output level and mute per band

Phase reverse switch per output

Switchable 25 Hz subsonic filter on each input for low-frequency driver protection

"Sum" function provides low-level mono output for subwoofer operation

Shielded toroidal mains transformer for minimal noise interference
Technical Info
Inputs Connectors: XLR

Type: Electronically servo-bal;anced, HF Filtered

Impedance: Balanced >50 kOhm, unbalanced > 25k Ohm

Max. Input Level: +22 dBu typical, balanced or unbalanced

CMRR: >40 dB, typical >55 dB @ 1 kHz

Outputs Connectors: XLR

Type: Electronically servo-bal;anced, HF Filtered

Impedance: Balanced >60 Ohm, unbalanced > 30 Ohm

Max. Output Level: +20 dBm balanced/unbalanced

Performance Bandwidth: 20 Hz to 20 kHz, +0/-0.5 dB

Frequency Response: <5 Hz to >60 kHz, +0/-3 dB

S/N Ratio (Ref.: +4 dBu, 20 Hz to 20 kHz, unweighted): 91 - 95 dB

Crossover Filter Type: Linkwitz-Riley, 24 dB per octave, state-variable
Mono Mode Frequencies: Low/High: 44 to 930 Hz (x10=440Hz to 9.3 kHz)
Low/Med: 44 to 930 Hz (x10=440Hz to 9.3 kHz)
Mid/High: 440Hz to 9.3 kHz
Stereo Mode Frequencies: Low/High to: 44 to 930 Hz (x10=440Hz to 9.3 kHz)

Dimensions: 1-3/4 x 19 x 8-1/2 in. (44.5 x 482.6 x 217mm)
Weight: Approx 6.6 lbs. (3 kg)
 
Jack and I have both posted work with CX3400 earlier in this thread, using passive HF compensation.

Can you do it with a quality parametric instead? Yes, if you have the requisite measurement gear.

Another member used DEQ2496 here.... :yes:
 
Don't use electrolytics. They're nonlinear, easy to measure how bad they are. They're fine for power supplies, in some cases for bypass when DC biased. But in general, avoid them for crossovers.

Polypropylene caps aren't that expensive, the largest you'll need are 20uF and they're only about $5 each.

About implementing these crossovers ahead of a biamp setup, what I'm saying about "the same signal" is you want the same transfer function provided by the passive circuit to be provided by any other proposed solution, active, line level passive, digital, etc. It isn't impossible, and there are some benefits when done right. But no matter what path you take, make sure the signal applied across the drivers is the same as is generated by the passive circuit provided.

It's not a straight Butterworth, Bessel or Linkwitz-Riley, nothing like that, not even close. So you actually need a passive filter, even if you go active. Or you can do it with a digital filter, one that implements an analog filter in software, sort of like what the ICD in the Smith & Larson system does. Point is, it isn't just a 1.2kHz 24dB/octave L-R crossover or anything like that.

I developed a Pi crossover based the Steve Bench 6DJ8 active unit, five or six years back. I modeled it in Spice, just like the passives. So that's one possibility:

Another option is to go with a line level passive crossover:

 
One more for ya, Wayne

Thanks for the wealth of info.

One more question.

Does the lowpass section of the 4pi need to be changed for the Dayton 15" I want to use?

The spec I was concerned about is the 1.71 Le for the Dayton versus the 1.07 Le on the Eminence Omega 15.

Other than that, the woofers look similar
 
How about motor run caps. They work fine for me. They are also pretty cheap if u get it from a local appliance stores. I know some people have strong feelings about this. I've used them in preamp and they sounded good! They are not to be confused with motor start caps though. My 2cents.
 
From the published response chart of the Dayton PF385-8, I'd say it was a no go. There's a fairly large breakup peak up high that might make it sound bad. The Omega 15 doesn't cost any more, and it's a little cleaner up high. Both have a peak just on the edge of the passband, but the Omega is a little smoother. The JBL 2226 is really nice, no peak at all, but it costs more.

Motor run caps sound nice to me, at least the ones I've used. They are a little large, but you can always wire them off board.
 
Ok....I have been lazy. Sorry

I dug up my Loudspeaker design cookbook.

It appears that the lowpass is a 3rd order network.

The C5 and R3 is an impedence equalization circuit.

I ran a couple of checks on the values, and determined what they "should" be. For the Eminence Omega 15.

(Subject to actual measurements)

The C5 = 23.88
R3 = 6.6 ohms

Dayton 15

C5 = 28.6
R3 = 7.7

I am assuming you chose the 8 ohm resistor, because they don't make a 6.6 ohm 100w resistor.

Maybe I answered my own question. The Dayton should be fine, maybe go with the 30uF cap instead.

Jake
 
Dayton a no go?? !

I looked at the schematics for both the eminence and the Dayton before thinking the dayton was a good choice.

The eminence is graph looks very similar, IMHO.

http://www.parts-express.com/pdf/290-430s.pdf

When you refer to the "break up", where exactly are you referring.

Maybe the slight peak at 1.5-2.5k? It seems that is past the crossover over frequency of 1.2K, that was chosen.

If not there, maybe you are refering to the peak between 1k and 1.5k. where the rise is about 5-6 dB. At that point, the eminence appears to mimic the dayton (or vice versa), because that is a 15" drivers naturally peak, from what I understand, and is figured into the crossover.

Maybe, I can't really figure out how to read charts.

The reason for the Dayton choice, is that is on sale for $45 dollars less per driver right now, with free shipping.

Jake
 
Yes!

Motor run caps sound nice to me, at least the ones I've used.
Click to expand...

I've found someone who speaks my language!:D I have them in my crossover as well. And of course some in my PSU. :banana:
 
JakeB said:
Ok....I have been lazy. Sorry

I dug up my Loudspeaker design cookbook.

It appears that the lowpass is a 3rd order network.

The C5 and R3 is an impedence equalization circuit.

I ran a couple of checks on the values, and determined what they "should" be. For the Eminence Omega 15.

(Subject to actual measurements)

The C5 = 23.88
R3 = 6.6 ohms

Dayton 15

C5 = 28.6
R3 = 7.7

I am assuming you chose the 8 ohm resistor, because they don't make a 6.6 ohm 100w resistor.

Maybe I answered my own question. The Dayton should be fine, maybe go with the 30uF cap instead.

Jake
Click to expand...

I designed the four Pi loudspeaker using actual acoustic measurements. The crossover component values chosen are what gave it smoothest response.

The truth is, Zobels are pretty low tolerance devices. You can usually fudge those values quite a bit, like around 20%, with no change in response. But like I said, I used actual measurements when developing the crossover, and selected the Zobel values for what gave smoothest response. They're not textbook values.

JakeB said:
I looked at the schematics for both the eminence and the Dayton before thinking the dayton was a good choice.

The eminence is graph looks very similar, IMHO.

http://www.parts-express.com/pdf/290-430s.pdf

When you refer to the "break up", where exactly are you referring.

Maybe the slight peak at 1.5-2.5k? It seems that is past the crossover over frequency of 1.2K, that was chosen.

If not there, maybe you are refering to the peak between 1k and 1.5k. where the rise is about 5-6 dB. At that point, the eminence appears to mimic the dayton (or vice versa), because that is a 15" drivers naturally peak, from what I understand, and is figured into the crossover.

Maybe, I can't really figure out how to read charts.

The reason for the Dayton choice, is that is on sale for $45 dollars less per driver right now, with free shipping.

Jake
Click to expand...

It might sound good, I don't know. The peak I'm talking about is the one around 1.5kHz. It is at the edge of the band, so the crossover will certainly attenuate it, but its presence will probably still be heard.

For $45.00, it's probably worth a try. Chances are it's an Eminence driver anyway, probably very similar to the Omega 15. Might even be the same part, or maybe with just a tiny change. Eminence's biggest market is OEM drivers, and many times they're very similar to their retail offerings. The thing is, I know the Omega 15 measures pretty good when installed in the four Pi loudspeaker. It's peak is a little smaller and lower Q, and isn't there in the finished loudspeaker.

One thing that usually helps, is that off-axis output from 1kHz to 1.5kHz is reduced. You'll notice a gentle increase in on-axis output in the octave around 1kHz, even in a driver with very well damped breakup, like the JBL 2226. This is because directivity is collapsing. But at 20 to 30 degrees, the output at 1kHz is reduced, approximately equal to the level an octave above and below it. So the power response is even, averaged over all angles.

Breakup modes are a different matter, of course. But the on-axis peaks caused by midwoofer cone breakup are caused by concentric flex, so they tend to be reduced off-axis. They tend to be worst on-axis, somewhat less pronounced off-axis, and then back again at large angles, forming side lobes.

So the long and short of it is the peak you see on-axis is smaller off-axis. When you average the sound level across all angles, the power response is usually pretty even. But I'd still far prefer a cone with well-damped breakup modes. The polars are more uniform and it just sounds cleaner.
 
Glad to help. Not usually able to be online as much, but have been lately.

Probably should limit the conversation here to Ewave topics. Keep the four Pi stuff over on my forum. I don't mind talking about my speakers, and since the crossovers are pretty much interchangeable, I think a discussion of their crossovers is germane here. But I don't want to hijack the thread.

Maybe I shouldn't have posted a link. Honestly, it's all the same stuff to me - the Ewave and the four Pi are brothers, almost twins. So, as far as I'm concerned, it's fine to talk about either of them. But I don't want to offend anyone.
 
Another woofer question.

Well, I am actually using the E-wave horn, JBl, and the Selenium d210ti.

So, I think this is the relevant place.

Ok, Wayne,

How about this one.

290-577 - Eminence Definimax 4012HO 12" Driver

http://www.parts-express.com/pdf/290-577s.pdf

Very linear. Has the shorting ring for low distortion.

Good specs all around. $189 bucks, so similar to the Omega 15, but with a shorting ring. I just want the biggest bang for the buck.

Seems like a real winner. 95db Sensitivity is about 2dB low from the Omega, but according to your 4pi posted response graph, and 10db padding on the tweeter, this would work well.

The d210ti is spec'ed at 107 dB not the 105 of your Eminence pds2002.

In addition, with the box gain of about 1dB in the low regions, it should be pretty smooth, on paper, and According to my WinISD box plot.

Jake
 
Very good.

I used to use the Eminence Magnums, which are what those are, renamed. They're good drivers, but not as good as the JBL's, in my opinion. Their shorting ring works, according to measurements, but not as well as the JBL drivers.

Regarding the D210Ti, use the same R1/R2/C1 components as the DE250. Both are about 2dB hotter than the PSD2002.
 
Yes Wayne talk speakers, yours mine whatever, it's all relavent.

Links to your speakers have been helpful to me when doing research. :thmbsp:
 
Spice me.

I went away trying to learn Spice. It's too spicy for me. I can't handle it. On a serious note. What am I suppose to do with it? Say I want to play around with R1 R2 C1 values. Where do I put the numbers? What functions am I suppose to use? Sorry Wayne. I am a bad student. :no: Even your "student version" is too hard for me.
 
mrTT said:
I went away trying to learn Spice. It's too spicy for me. I can't handle it. On a serious note. What am I suppose to do with it? Say I want to play around with R1 R2 C1 values. Where do I put the numbers? What functions am I suppose to use? Sorry Wayne. I am a bad student. :no: Even your "student version" is too hard for me.
Click to expand...

Boy am I glad you had the guts to ask this one...I wa stoo embarrassed! I'm all ears as I am sure to be in the same situation.

russellc
 
Wayne Parham said:
Very good.

I used to use the Eminence Magnums, which are what those are, renamed. They're good drivers, but not as good as the JBL's, in my opinion. Their shorting ring works, according to measurements, but not as well as the JBL drivers.

Regarding the D210Ti, use the same R1/R2/C1 components as the DE250. Both are about 2dB hotter than the PSD2002.
Click to expand...

Can you provide a link to the DE 250 schematic? When I last inquired I think the crossover was for PSD 2002. I assume the difference is in the compensation?

thanks, P.S. I found it on the Audioroundtable forum, thanks! I think "Updated Theatre 4s now in operation" I assume the crossovers are the same as the smaller pro Pi 4?

Russellc
 
Pop Quiz!

With the knobs on my two E'Wave L-pads set to 12:00 ("Normal," mid-way,) the resistance readings on my trusty Fluke DMM are as follows:

Series = 3.4, 3.5 Ohms
Parallel = 22.8, 22.1 Ohms

What is their mean dB attenuation using a nominal 8-Ohm HF compression driver?

Extra Credit:

What is that of each of them set to this position?

And the arithmetic mean of those two values?
 
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