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Multi-Way Conventional loudspeakers with crossovers

Trying to mellow out Klipsch KG 4.5 tractrix horn
Trying to mellow out Klipsch KG 4.5 tractrix horn
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Old 10th August 2018, 02:52 PM   #11
TBTL is offline TBTL  Germany
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Could you make a frequency response measurement? Preferably 1/24 octave smoothed, not more. Without, you're shooting in the dark.
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Old 10th August 2018, 02:53 PM   #12
rongon is offline rongon  United States
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Trying to mellow out Klipsch KG 4.5 tractrix horn
I wish AllenB's update post had been available to me back when I had those speakers. I sold them off, long ago.

I followed a lot of suggestions and tried a lot of things trying to get these speakers to work for me. I tried:

- 30 ohms was as low as I went with a parallel R on the tweeters
- Zobel network on the woofer (and kept it there)
- lined cabinet walls with felt (made a slight difference in the upper mids)
- Put a cross brace between baffle and back panel (helped un-muddy mids a little)
- Tried some poly fill behind the tweeter and at the bottom of the cab, out of the way of the woofer and port (trying to un-muddy the lower mids/mid-bass)
- Installed Crites metal diaphragms in the tweeters, which gave a clearer presentation to the highs

The final problem I found was a 'honk' in the mids, which made male vocalists sound bloated and just plain peculiar. I noticed it particularly on Joe Williams' voice (classic recordings with Count Basie, etc.). This coloration sounded glorious on electric guitars, really made electric blues recordings sound great. But I listen to a lot of of different music besides that. Once I heard that, I realized the problems were in the crossover region, very likely related to the upper range of the 10" woofer. Since I'm not capable of re-designing crossovers to compensate for anomalies in drivers with no published specifications, I threw in the towel and sold off the speakers.

Those speakers did give me a taste of what a 2-way with horn tweeter can do. On a whim, I bought a pair of JBL LSR305, to get a taste of what an oblate-spheroid waveguide-type setup can do. They're still in my system, driven by a tube preamp with balanced outs I built to warm them up to my liking. I have a small listening room, so the LSR305s do just fine. Great little speakers for the money, IMO.

I wish I could come up with the coin to try a pair of diysoundgroup's Fusion 12 (Jeff Bagby design) or maybe a pair of pi Speakers (Wayne Parham). But I got bills to pay, so the little JBLs stay...
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Last edited by rongon; 10th August 2018 at 03:00 PM.
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Old 10th August 2018, 05:22 PM   #13
system7 is offline system7  United Kingdom
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You just take one look at a 1.5kHz bass filter on a 10" with 1mH bass coil, and 2R plus 33uF shunt, and you know it's gonna be trouble!

Eminence would use 2mH and 10uF for 2.5 kHz. 10" bass also tends to break up around 2.5kHz.

Which is all to say, 2mH and 4R and 16uF is gonna have much better tilt or flatness. You then need to take the tweeter down 3dB and hope Klipsch have built a reasonable 1.5kHz filter for it. Which I am also dubious about here.

Anyway, typical 10" bass adjusted down with 2mH/4R plus 16uF below. You ought to be able to do something with that. Even tuning by ear.

Whole thing is then best tested on known good and dynamic live recordings. Count Basie and Francis (It might as well be Swing), or Peggy Lee and George Shearing (Beauty and the Beat) works for me. I like the old stuff. It was a glorious time in music. (Adds gratuitous image of latest retro speaker.)
Attached Images
File Type: png Bass Adjustment 1mH to 2mH and other.PNG (21.2 KB, 115 views)
File Type: jpg system7 speaker with Count Basie and Frankie.jpg (74.0 KB, 117 views)
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Old 10th August 2018, 05:55 PM   #14
rongon is offline rongon  United States
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Trying to mellow out Klipsch KG 4.5 tractrix horn
Thanks for that. What is a "Celestion 25"?

I collected a pair of Eminence B102 10" 8-ohm woofers with whizzer cones and a pair of SEOS-10 waveguides with suitable 8-ohm compression drivers. I chose the B102 because it goes pretty high up in the mids, without a lot of frequency response deviations above 2kHz. I was hoping to make a high-efficiency 2-way suitable for low power tube amps. I've had a couple of false starts, but abandoned the project. Maybe I should give it another go.

That 2mH/4R and 16uF is the LPF for the woofer? Does that 4R go in series with the 16uF shunt cap?
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Last edited by rongon; 10th August 2018 at 05:57 PM.
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Old 10th August 2018, 06:25 PM   #15
system7 is offline system7  United Kingdom
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You don't know what a Celestion Ditton 25 was?

Click the image to open in full size.

A 12" bass is hard to level match with a regular tweeter, so Celestion had the bright idea of using two for an extra 6dB.

It is, of course, 2mH series bass coil, and 4R and 16uF in series in the shunt. I just used a Celestion 25 sim to get a quick result for a 10".

I am sure the 10" B102 Legend and a horn tweeter is doable.
Speaker Detail | Eminence Speaker

Zu and the WLM Grand Viola used it.
6moons audio reviews: WLM Grand Viola Signature MkII

It looks tidy enough for 2.5kHz crossover. I think the whizzer just adds a bit of mass and damping without producing much top end. Traditionally a good bass guitar speaker which has been slightly modified lately. What's holding you back? There are some good designs at the Eminence site, including co-axials with stock crossovers, which aren't fundamentally different IMO.
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Last edited by system7; 10th August 2018 at 06:29 PM.
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Old 10th August 2018, 06:41 PM   #16
rongon is offline rongon  United States
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Trying to mellow out Klipsch KG 4.5 tractrix horn
You're inspiring me!

I thought you might mean the Ditton 25, but the photo was of something completely different.

Rain is forecast for this weekend, so I may end up pulling out the speaker project and giving it another quick try. I'd start with the woofer crossover. There are a couple of spikes in the B102's response that will need to be tamed with notch filter or two. Looks to me like the one at 2.8kHz is close enough to the pass band to really matter.

What I should do is learn how to use REW with the USB mic I bought and get some quick 'n dirty frequency response measurements. That way I could use objective data to get close to a target response, instead of relying solely on my inexperienced (but old and beat up) ears.
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File Type: png EminenceB102_peaks.png (47.1 KB, 85 views)
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Old 10th August 2018, 07:02 PM   #17
system7 is offline system7  United Kingdom
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The photo was my current fun build. Based loosely around a WLM La Scala. Do you see the resemblance? I decided the tweeter was rubbish though, and changed it.

Click the image to open in full size.

I'd just try the stock Eminence PXB2 2K5CX 2.5kHz crossover value of 2mH and 10uF and give the bass a listen. I think this crossover is considered fairly universal. That peak at 2.5kHz (the first breakup mode) is quite expected and should be already tamed by the crossover. The higher one shouldn't bother you at all. It might be a little resistance in the shunt is a good thing, time will tell.

TBH, I don't know much about horn drivers or living rooms the size of a barn. This is the UK.
Attached Images
File Type: jpg Eminence Crossover PXB2 2K5CX.JPG (16.2 KB, 6 views)
File Type: png Eminence PXB2 2K5CX.PNG (22.4 KB, 8 views)
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Last edited by system7; 10th August 2018 at 07:14 PM.
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Old 10th August 2018, 07:28 PM   #18
rongon is offline rongon  United States
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Trying to mellow out Klipsch KG 4.5 tractrix horn
Thanks again.

I remember from when I had it wired up that I was able to get good enough bass, and the high frequencies were fine using a tractrix horn designed by Fastlane with Selenium compression driver. It was the midrange that gave me problems, of course. It was sooo close, but there was still a bit too much energy in the 800Hz to 2kHz range for classical music. Violins sounded OK, but too shrieky. I'll try it again with this 2uH/10uF 2nd order LPF combination. I don't know what kind of HPF I'll use on the tweeters.

The reason I went with a tractrix horn is that that type should require the minimum amount of FR compensation to get close to flat. What I didn't know was that there are pretty weird lobing effects associated with tractrix horns in near-field listening conditions. You have to hold still or the tonal balance changes drastically. Not fun.

Quote:
TBH, I don't know much about horn drivers or living rooms the size of a barn. This is the UK.
My reason for using horns was for controlled dispersion rather than for long-throw and super-high sensitivity. I can do fine with 90dB/1W/1m, although higher sensitivity doesn't hurt.

I can use my LSR305s as a target to hit. I didn't have them the last time I tried to get the big 2-ways working.
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Old 10th August 2018, 09:44 PM   #19
system7 is offline system7  United Kingdom
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You've made me think. I was just trying a couple of pairs of speakers with classical music on CD. And the winner was... Monitor Audio R300-MD modified...

Click the image to open in full size.

A Robin Marshall 8" Elac paper and 3/4" Seas metal dome selection, with a KEF type crossover I built that he would recognise:

Click the image to open in full size.

Closed box is just a natural for classical. You need low colouration, which usually means low efficiency. Low distortion and extended frequency response. All a bit Harbeth really.

I'm not sure you can do this with PA drivers. Much as I love the liveliness of high efficiency. And, TBH, anything you do in two-way is better in a three-way.

I was looking at Jeff Bagby's Fusion-8 Alchemy. It's a bit more sophisticated than Eminence crossovers, being third order bass around 2.5mH/8uF/1mH, and crossing at about 2.5kHz, well below the Beta 8A's breakup. Second order tweeter with attenuator. It must help to get well away from breakup. I suppose the only way to find out, is to build something.
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Old 10th August 2018, 09:53 PM   #20
bentoronto is offline bentoronto  Canada
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Trying to mellow out Klipsch KG 4.5 tractrix horn
And the lesson is: if somebody starts a thread with nothing but vague emotions about the sound problem they have, just pay no attention.*

REW (honourware or free for the ungrateful) even using a laptop mic** would have been appropriate and shown some respect for all the folks who tried to contribute. Or even pointing out some accessible recording that demonstrated the problem.

B.
*OP didn't even have the decency to feedback on the bad results from the advice provided.
**I've posted comparisons to my calibrated mic with the Mac Air mic, here's the link:

You can use your laptop mic
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Last edited by bentoronto; 10th August 2018 at 10:10 PM.
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