active two way with HF144 compression driver and LTH142 horn

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Hi,

After a few years being happy with my "classic" econowave build, I've decided to gradually replace them with some active two ways in a similar, but hopefully "more is better" vein.

I've ordered in a pair of Faital Pro HF144 compression drivers with corresponding LTH142 horns. I've yet to settle on a matching low frequency driver - most likely a 15", but I am getting some instant gratification thanks to MiniDSP by just sitting my existing speakers on their sides with the new horns & CDs on top:

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One thing I have noticed is for both of my HF144 drivers, although my measurements are relatively close to the factory response graph, mine have a big "notch" at about 15Khz not present in the factory curve:
my measurements (at 1M, both "left" and "right" smoothed @ 1/8 per octave ):
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response from the FaitalPro site:
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although I dont think I can hear up that high, it's still kind of annoying 🙂

Col came over and we checked them with woofertester3 and they test out fine impedancewise.

Can this be explained by room effects or me not measuring the same was as Faital do? Should I even care about a notch in frequency response up that high?

I've got more involved discussion in a blog post here:
beyond econowave : Faital Pro HF144 compression driver with LTH142 Tractrix horn | MiniRIG

A gated measurement, of both HF & LF drivers (crossed at 900hz) with some miniDSP correction shows the HF response in a bit more detail:
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apart from the above they are sounding quite good just working with my existing speakers, looking forward to the next step of choosing some woofers in a decently sized bass reflex box to go with them.
 
I think the notch at 15k is still there in the Faital Pro's measurements.... it's just heavily smoothed over. Try 1/3 octave smoothing on your measurements, then compare the two. I think you'll find they are more similar than you think.

Joe
 
I think the notch at 15k is still there in the Faital Pro's measurements.... it's just heavily smoothed over. Try 1/3 octave smoothing on your measurements, then compare the two. I think you'll find they are more similar than you think.

Joe
The factory graph - available in more resolution at http://www.faitalpro.com/products/files/HF144/8/HF144_curves_8.pdf seems to have a few more angular bits in it that would indicate to me that it isn't that smoothed... I could just email them and ask I how they made it I suppose. But yes, there is kind of a sign of the notch there.
 
I wouldn't worry about the notch at 15kHz. There's very little information up there anyway.

It's funny in another thread (re: one of my DACs) I'm discussing the DAC not being able to do 192khz while handling 96khz fine.. but a simple test with sine waves generated in audacity and my 45 year old ears struggle to hear anything beyond 14khz.

However, I would take a closer look at the hump centering at 500Hz (bottom plot). I find this makes voices nasal.

I've got a later iteration of my MiniDSP crossover config which I need to add where I'm crossing over at 500hz instead of 900hz (which the LF144 appears to handle just fine!) and have a bit of attenuation around 500. But as I did my measurements indoors I'm guesstimating as I'm getting a lot of room effects around the crossover point in the measurements (auto gating according to Holmimpulse).
Some outdoor measurements are on the cards to reomove room effects, especially if some smaller temporary woofer enclosures become available, my 120L econowave cabinets weren't made with ease of moving in mind 🙂
 
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... but a simple test with sine waves generated in audacity and my 45 year old ears struggle to hear anything beyond 14khz.

Personally, I'm not bothered by sine tones at 15kHz. What I'm really interested in are Tone and Harmonics. It is subjective but that's what my speakers are for, my listening pleasure.

The bump at 500Hz could be due to floor bounce. If the voices doesn't sound nasal, it's fine. Measurements can be deceiving sometimes.
 
Personally, I'm not bothered by sine tones at 15kHz. What I'm really interested in are Tone and Harmonics. It is subjective but that's what my speakers are for, my listening pleasure.

That's essentially what I said. But I am a follower of the Zilch (of Econowave) mantra of "more data, less wank", and these compression drivers have a manufacturer advertised response up to 18khz.
I am listenening to, and enjoying them 🙂. But then again they can be used in a non PA setting well under the 800hz frequency mentioned as well.

The bump at 500Hz could be due to floor bounce. If the voices doesn't sound nasal, it's fine. Measurements can be deceiving sometimes.

agreed.

I have found a few mentions of German web sites that appear to agree with my measurements according to google translate - I'll move on with other fun stuff.

One of these is I've ordered some inexpensive Pyle PH916 constant directivity waveguides - be interesting to compare them with the Faital Pro tractrix horns.

I also want to do some directivity heatmap plots. as far as I can tell there is no free softare solution to do this, the easiest path to getting it done is the paid version of ARTA. This will allow me to fully compare the Faital and Pyle waveguides, and get the crossover point with the LF drivers sorted out.

Also have been looking at 15" drivers with better bass than the Eminence Delta 12LFA. I'll set them up in a simple bass reflex enclosure.

Possible candidates include:
Beyma 15B100R
Beyma SM115/N
RCF LF15N401
B&C 15TBX100
Selenium 15WS800
Lorantz C390X B1
(etc).. i.e. a range of high efficiency "PA" drivers with lower Fs that look suitable for hifi use as well, that I can cross over at between 500 and 1000 Hz
 
I got a pair of lovely Australian made Lorantz C390X B1 15" bass drivers from ebay in very good condition, so these will make up the low frequency part of this two way project.
Apart from the drivers themselves the seller added in a bonus PA bass reflex cabinets he had them mounted in - while not the best quality it is great they came with them as I can get some instant gratification and start using them straight away:
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Their design is quite handy, as turned upside down the 15" driver is very close to the waveguide, which is how I want the good enclosure I will build to be arranged.

For now I've bypassed the basic PA crossover in the unit and hooked up directly to the amp via some cables fed through the bass reflex ports.

In room measurements are pretty similar to the old drivers, as below 600hz there are a lot of room effects - when I get time and decent weather I'll do some outdoor measurements.
So I now have an even more "PA" looking two way active system with these temp. boxes:
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Specs for the driver are at this link:
http://www.lucasmiles.com.au/content/lorantz/A-C390X-B1-8.pdf
Sold here, though I got them substantially less than this on ebay 🙂
Lorantz Bass Speaker C390X B1
 
As to the dip at 15khz....I agree you're probobly not missing much BUT for the sake of the discussion, I'd try mounting the horn on a 36" square of baffle and re measure....bet it smooths out quite a bit.

That Faital pro horn looks like a winner!
 
Are you sure you didn't see any blips in the impedance around 9-10kHz?

Try measuring the speaker on the floor near the middle of your room pointing at the ceiling to get down to crossover range indoors.

Btw, this looks like you're heading for directivity approximating a smooth taper from 360° to 60°, which is quite a bit different from the 360°-to-90°-and-then-hold-it CD type of design.
 
As to the dip at 15khz....I agree you're probobly not missing much BUT for the sake of the discussion, I'd try mounting the horn on a 36" square of baffle and re measure....bet it smooths out quite a bit.

That Faital pro horn looks like a winner!

The Pyle PH916 "Constant Directivity" waveguide I ordered last month showed up and I have tried it with that - interestingly the 15Khz dip does NOT seem to be there. This is measuring 1M away with mic pointed straight at the compression driver.

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Right now I'm crossing over @ 500hz with LR24. The Pyle waveguide is only specced from 1000hz up however but I'll see how I go with more measurements. No gating, smoothed @ 20 per octave.

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PH916 with flat EQ, and some miniDSP EQ applied to flatten the response.

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Corresponding with/without EQ measurements done with the Faital LTH142 horn, all other things constant.

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for interests sake.. with NO waveguide (i.e. naked compression driver sitting on the edge of the speaker box).

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PH916 sitting on top of the PA cabinet.

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The two waveguides next to each other.

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special audiophile high density kiln fired red terracotta compression driver support unit

apart from.. or maybe because of.. the better measurements, I think the Pyle PH916 sounds better .. going into Audiophile waffle opinion mode I do think it has a bigger, more vivid sound. But that could just be "new toy" syndrome talking.

Are you sure you didn't see any blips in the impedance around 9-10kHz?

I have loaned WooferTester3 from a mate so I will redo the impedance measurements and take some screenshots, as I want to measure the Lorantz 15" woofers as well.

Try measuring the speaker on the floor near the middle of your room pointing at the ceiling to get down to crossover range indoors.

Btw, this looks like you're heading for directivity approximating a smooth taper from 360° to 60°, which is quite a bit different from the 360°-to-90°-and-then-hold-it CD type of design.

I've still been too lazy to move stuff around to get clean down to the crossover region so far. But I will.. and also get out the "lazy susan" turntable rig I have stashed away to do some directivity measurements, both with the Pyle Constant Directivity waveguide and the Faital Tractrix horn.
 
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Still using the pyle?

No, I've movied on quite a bit since my last update in this forum: I went to an 18Sound XT1464 which is by far the best so far. I'm sticking with that. The Pyle was OK for the price though.

I've also made a plywood 140L bass reflex cabinet better suited for the Lorantz woofer and stained it so it's now up to WAF standards:

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further info here:
beyond-econowave | MiniRIG
and here:
active 2 way speaker using FaitalPro HF144 and Lorantz C390X B1 continued... - DIY Audio Projects - StereoNET
 
Is the 15 kHz hole still there or is it coming from the driver itself ?
Chalres

From memory the 15khz hole not as big with the XT1464 and is mostly visible directly on axis, response a lot smoother off axis (how I use the speakers)

Hi Zog, do you have individual measurements of bass and tweeter ?

It would be nice to see bass, tweeter and resulting FR in one plot.

Thanks in advance.

yes, I'll gather up a few graphs I've made and post them to expand on this.
 
I doubt anyway whether the 15 kHz hole is giving the slightes trouble at all.

I have a small Beyma coax which is showing quite some peaks and dips above 10kHz and it doesn't sound harsh or coloured or whatever.

But I wonder whether that driver/horn combination here can be mounted into a woofer cabinet for HiFi purposes. How would the horn cope with the woofer's back-pressure ? Would it vibrate a lot (i.e. how sturdy is it ?) ? And is the HF driver tight against back pressure (i.e. no air air leaks between the neo magnets) ?

Regards

Charles
 
Hi Zog, do you have individual measurements of bass and tweeter ?

It would be nice to see bass, tweeter and resulting FR in one plot.

Thanks in advance.

here's one example, an earlier config generated by stereo.net.au member henry218 (thanks!!) I was experimenting with a few months ago that I have decent graphs of:

done 120cm on axis, with 24/octave smoothing, with miniDSP correction applied:

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Now the cosmetic stuff with the enclosures is sorted out I can get back to measurements and miniDSP refinement and ACD spreadsheet.
 
I doubt anyway whether the 15 kHz hole is giving the slightes trouble at all.

I have a small Beyma coax which is showing quite some peaks and dips above 10kHz and it doesn't sound harsh or coloured or whatever.
Yes, for my purposes it doesn't matter either, I think I initially was over obsessing because the manufacturers specs say otherwise.

Here is an outdoor directivity plot I did, smoothed @ 12/octave, taken at 2M distance on axis, with the mic up high pointed at the middle of the waveguide.

compression driver and waveguide, no EQ or crossover except the 76uF compression cap:
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But I wonder whether that driver/horn combination here can be mounted into a woofer cabinet for HiFi purposes. How would the horn cope with the woofer's back-pressure ? Would it vibrate a lot (i.e. how sturdy is it ?) ? And is the HF driver tight against back pressure (i.e. no air air leaks between the neo magnets) ?

Regards

Charles

The XT1464 is a very well made and sturdy waveguide. One reason I've decided to just leave mine "out in the open". Even comes with nice plastic gasket stuff around the rim.

But the "raptor" speaker project uses them in cabinet with tower speakers:
http://www.htguide.com/forum/showthread.php?35812-The-Raptor-a-10-quot-MTM
 
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