Econowave style 15”

Thanks to @Patrick Bateman I’ve got a set of qsc 10”x14” 152i waveguides that I want to try in a 15” two way with these on sale faital 15fh500 woofers (ordered,should be here next week) that are supposed to be quite close to the 2226h in performance?https://faitalpro.com/en/products/LF_Loudspeakers/product_details/datasheet.php?id=151060100

I wanted these waveguides to try with the eminence N151-M https://eminence.com/products/n151m_8 after seeing this thread where PB highly regards the combination https://www.diyaudio.com/community/threads/improved-saw-lens.350889/page-2

The woofers were just too good of a deal to pass up (about half retail) so even if they don‘t work here they’ll get used somewhere.

I reckon designing a reflex box to 30 hz +/- shouldn’t be too difficult and will have to measure each driver off axis to find the best directivity match for XO …….would like to keep it 2nd order if possible (looks quite doable)

Any thoughts on this? Yes I know the XO will be right at (or below) the N151-M fs of 1.24khz but apparently its good down to 1khz or less in this waveguide. Was wondering if @Patrick Bateman would be kind enough to elaborate more on the XO used in that testing?

thanks, Bob
 

GM

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At a glance and using the pioneer's octave spread polar response matching XO points, the woofer at ~1128 Hz/45 deg matches up to the 152i's 45 deg and IIRC the Econowave's XO at least started out based on Altec's M19 nominally 1200 Hz XO, so for me a close enough 'variation on a theme'.............. ;)
 
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As a sanity check, I would check the estimated cone displacement vs frequency on a tool like Hornresp. When it starts climbing to a sizeable fraction of a mm, power should be reduced. Low freq. cone displacement is likely to start messing with the compression ratio, resulting in amplitude modulation at HF. So extendimg the horn with a round over would probably give it a bit more head room I thinking.
 
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This ( JBL L45 Flare ewaves ) shows my favourite 15" eWave effort.

I like the look of the slightly offset horn ( as well as the effort to close the gap between the drivers two acoustic centers ).

IMG_9506 (Large).JPG
IMG_9546 (Large).JPG
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You'll want to make custom network ( of course ) for the components you're using.

:)
 
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Thanks to @Patrick Bateman I’ve got a set of qsc 10”x14” 152i waveguides that I want to try in a 15” two way with these on sale faital 15fh500 woofers (ordered,should be here next week) that are supposed to be quite close to the 2226h in performance?https://faitalpro.com/en/products/LF_Loudspeakers/product_details/datasheet.php?id=151060100

I wanted these waveguides to try with the eminence N151-M https://eminence.com/products/n151m_8 after seeing this thread where PB highly regards the combination https://www.diyaudio.com/community/threads/improved-saw-lens.350889/page-2

The woofers were just too good of a deal to pass up (about half retail) so even if they don‘t work here they’ll get used somewhere.

I reckon designing a reflex box to 30 hz +/- shouldn’t be too difficult and will have to measure each driver off axis to find the best directivity match for XO …….would like to keep it 2nd order if possible (looks quite doable)

Any thoughts on this? Yes I know the XO will be right at (or below) the N151-M fs of 1.24khz but apparently its good down to 1khz or less in this waveguide. Was wondering if @Patrick Bateman would be kind enough to elaborate more on the XO used in that testing?

thanks, Bob

It's all I can do to avoid hitting "buy" on those Faitals


But I currently have 3-4 projects going at the same time so I must avoid the urge

As far as the xover goes, I generally just do this: https://www.melaudia.net/zdoc/jml_crossovers_etf04.pdf

This topology doesn't seem to get used very often, but it generally yields a really nice phase response, without resorting to DSP for each channel.

I generally DO use DSP on all my speakers, but what I try to do is:

1) get the crossover "in the ball park" using conventional filters, ideally passive
2) And then I add in DSP for equalization and for high pass filters.

I think this is kinda "the best of both worlds." I do like full-DSP solutions, but as soon as you have multiple channels for each speaker, things get messy in a hurry, especially if you're doing multichannel. At my house, 2/3rds of the rooms with speakers in them, are common areas. Like my living room and my TV room. So it's not ideal to have a ton of equipment, just too many things to break, particularly since someone is always pushing buttons or unplugging things.

One drawback with the LeCleach crossover, is that the midbass or woofer needs to be about 8-12cm closer to the listener than the tweeter. There are two relatively easy ways to do this:

1) Built a Unity horn. Those mids are always ahead of the tweeter

2) or do a two way and angle the baffle

Since you're doing an econowave, the baffle is flat, which makes this trickier:

1) Easiest option is to just discard the use of crossover topologies with excellent phase response. I'm really on the fence on this one. In my Unity horn projects, I can definitely here an improvement in intelligibility. Then again, my Yamaha DXR12 speakers don't bother with flattening the phase (AFAIK) and they sound pretty darn good. My Unity horns and my Yamahas sound completely different, but each has it's own strengths.
2) The other option is to go full DSP and just delay things digitally

There are some cases where you can use a flat baffle and get that awesome phase response. But to do that, you generally need a fairly deep waveguide, and I don't think the QSC clones will qualify. They're about 5" deep IIRC, and that puts them on just about the same vertical plane as the woofer.

In conventional two ways, with a plain ol' tweeter, you get the opposite problem, which is that the tweeter often 'leads' the midrange or woofer by as much as 1/4 to one half wavelength at the xover point. That can make a real mess of the phase response.

By the way, if nobody wants to ingest the entire contents of the LeCleach crossover, the general idea is that the woofer is about 1/4 to 1/2 wavelength closer than the tweeter, and then the low pass filter is used to delay the woofer, so that the sound from both drive units arrive in phase. IE, if you were using plain ol' first order xovers, you wouldn't need to slant the baffle. (a low pass xover delays the output from the woofer, and the steeper the filter, the longer the delay.)

This post is long and convoluted, so please keep in mind that the ideal solution might just be to 'tweak' the crossover that's been used in various variations of the Econowave. IE, I'm 95% certain that there's a revision of the Econowave out there that uses the QSC waveguide instead of the JBL waveguide used in the original Econowave.
 
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Thanks for the in depth response!

Hence the shim/extender for the waveguide on the flare Ewaves above.

Would a second order on the woofer and first order on top be enough. Run the first order at a bit higher point and let the drivers overlap, looks like the fr curves for the N151-M might support that and it drops off like a rock @ 1k anyway. Could also mount the woofer from the backside of a thick baffle (round over the front) with the waveguide on the front side.
I run dsp between sub and mains at the moment with passive filters in the mains, i’ve been looking at that new mini dsp 8 channel setup so maybe this is a good excuse!
 
Yes, have calibrated USB mic, REW, and DATS 3 with plans of downloading a circuit simulator like vituix cad or win pcd……..
Is there a circuit simulator/designer thats easier to use than others? Remember I ride the short bus when it comes to computer skilz! And yes I have seen that the usb mic is not at all good for phase measurements, any recommendations there? Focusrite scarlet is supposed to be a good interface, what might be a good mic to pair with it?
Was just skimming through that JM LeCleach paper that PB linked to, looks quite interesting I think I’ll have to sit down and digest that. Thanks for that @Patrick Bateman and thanks to @djn for that gracious offer.
 
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The USB mic will need careful attention when used for crossover work, since the USB bus doesn't send data in realtime and you need to set up an extra speaker to use as a timing reference. USB mics are a case of oversimplifying.. (EDIT: I just saw your edit regarding these mics so this paragraph is no longer necessary)

Vituixcad is capable of doing what you want, but the instructions encourage doing only a full polar crossover, which is more than you are asking at this point. Xsim is probably a tad easier to use. I believe win pcd can as well, but I haven't worked with it extensively.
 
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Since you're doing an econowave, the baffle is flat, which makes this trickier:

By the way, if nobody wants to ingest the entire contents of the LeCleach crossover, the general idea is that the woofer is about 1/4 to 1/2 wavelength closer than the tweeter, and then the low pass filter is used to delay the woofer, so that the sound from both drive units arrive in phase. IE, if you were using plain ol' first order xovers, you wouldn't need to slant the baffle. (a low pass xover delays the output from the woofer, and the steeper the filter, the longer the delay.)
In Peavey's 15+CD products, SP2-XT & SP2(2004) the CD is 8" back from the front of the woofer. Simple 1 capacitor 2 inductor 1 limiter bulb crossover.
I have to say running a 1" CD N151M down to 1200 hz is iffy. Eminence recommends 1800 minimum on the datasheet. Plus those *****y horns eminence & P-audio sell for flat mount CD's are not 8" deep. An eminence CD N314T is good down to 800 hz and is better from 10000 to 16000 hz than the N151M. Costs more. N314X goes down to 500 hz but costs even more. In my parts kit for a 15"+CD I've been unable to find a flat back horn that is 13" wide, 7" tall, 8" deep, as the screw on horns for the speakers in the first paragraph are. SP2(2004) horns have rounded deges at the front.
Plus when Peavey increased 15" crossover from 1200 Hz (SP2-XT) to 1800 Hz (SP2(2004)) to maintain 6 db radiation angle of 90 deg they had to pinch the back of the cabinet in. Make it trapezoidal. This is a design feature that few home builders will want to copy. Not me.
 
I’ve got no problem with trapezoidal if it will help the cause…..already have the qsc 152i waveguides and if you read PB’s testing with the qsc/N151-M you’d probably be as surprised as I was. https://www.diyaudio.com/community/threads/improved-saw-lens.350889/page-2
Looks like for the 15fh500 I‘m going to need a 200 - 240 litre box glancing at it. @indianajo can you elaborate or point me in a direction to get a better handle on the trapezoidal box designs?
Thanks,
Bob
 
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Looks like I‘m going to need a 200 - 240 litre box glancing at it. @indianajo can you elaborate or point me in a direction to get a better handle on the trapezoidal box designs?
The SP2(2004) are O.D. 20.5" front, 12" back, 30" tall. Allegedly 3/4 birch plywood, although I haven't disassembled them to check. Tuned for 55 hz with 2 ports at bottom, 5" tall x 4" wide x 3" tall with long dimension on box outer edge. 2" deep.
 
Seems as though the trapezoidal thing isn’t that beneficial ? https://www.diyaudio.com/community/threads/why-trapezoidal.37831/

edit; just got the update from fedex…….woofers are in route for delivery today! I‘ve been waiting to pull the trigger on the N151-M until I saw some responses……..looks like theres not much to lose, I’ve got some extra 10” eminence delta’s they can pair with if this doesn’t work out. :cool:
 
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Seems as though the trapezoidal thing isn’t that beneficial ? https://www.diyaudio.com/community/threads/why-trapezoidal.37831/
Read that thread. Ha Ha Ha Ha Ha Ha Ha!
Peavey has sold tens of thousands of the SP2(2004) and is still selling a 1000 w SP2 version that doesn't meet the HD specs of the 2004 version. Full frequency 6 db spread of 90 degrees horizontal has been specified through the production run, with 54-1800 hz coming from a 15" woofer.
Dozens of experts on here have asserted a driver can't get horizontal dispersion over the wavelength of a woofer. Speed of sound 1125 tf/sec/1.25 ft =900 cycle/sec. So Peavey is guarenteeing horizontal dispersion twice as high as the experts say is the limit. The cabinet is trapezoidal. There are other design features inside that I can't measure, like a folded up elastomer sheet behind the woofer running at 45 degrees to horizontal & vertical.
I like to walk around the room without the sound changing. My SP2(2004) do that. Most builders on here declare victory if they get flat frequency response straight out front (only).
In addition, consider the supression of standing wave at speedofsound/width or 658 hz. If the depth of cabinet that is 20.5" is 1 inch, one doesn't need nearly as much fibrous stuffing to kill the bump at that frequency.
 
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I have no idea thats why i’m asking, so is this a result of the exterior side panel being on a negative cant thereby sending refections in a broader arc, or is it more to do with canceling internal waves?
My initial box size is looking like 42”H x 22”W x 20”D
and as long as it works @ 45 deg i’m ok with that