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Multi-Way Conventional loudspeakers with crossovers

JBL PT 100x100 waveguides, any experience? MPro?
JBL PT 100x100 waveguides, any experience? MPro?
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Old 26th March 2019, 07:04 PM   #101
norman bates is offline norman bates  United States
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+1
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Old 26th March 2019, 08:07 PM   #102
DualTriode is offline DualTriode  United States
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Quote:
Originally Posted by 300Z View Post
I agree and that's what alluded to earlier. When you add a network the impedance curve will change.
Hello,

What impedance curve is changing?

What you are talking about is measuring the impedance at the amplifier output where it connects to the speaker network. Sure, no problem the amplifier sees a much flatter impedance curve. If you zoom in and measure the impedance where it was originally measured, across the CD / Horn, the impedance and underlying resonance will remain as it was without the network.

By adding the external network what you are doing is equalizing the frequency response without correcting the underlying resonance. Your vowels will still sound nasal but just not as loud.

I am from the school that wants to flatten the impedance and FR of the CD /Horn as much as possible prior to adding the network.

Thanks DT
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Old 26th March 2019, 11:26 PM   #103
norman bates is offline norman bates  United States
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yes, it is hard to get rid of resonances (reflections) with eq.
They still ring down over time.
You can eq it flat but you may still hear it.

If you notch a peak, a frequency half or a third can cause it to ring at full strength (the harmonic sneaks past).

I also heard (not sure), you can eq a horn, but the level of resonances change based on volume levels (say 90db vs 100db).

The pt waveguide you have looks good, less reflections = more detail, more you hear into a recording.
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Old 27th March 2019, 12:24 AM   #104
Robh3606 is offline Robh3606  United States
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Quote:
I am from the school that wants to flatten the impedance and FR of the CD /Horn as much as possible prior to adding the network.
Hello DT

Yeah OK but it's natural to have at least 2 peaks in the curve. Its the nature of the beast. Also there is no external Band Aid you can put on a horn CD combo to reduce the peaks that will fix the real problem. It's no different than trying to fix directivity in a speaker with EQ.

Doesn't work because it is fixed by the design just as a horn resonance and discontinuities or HOM's in a waveguide/horn or issues with the CD phase plug interacting with the horn/waveguide.

You need to take Earl Geedes approach and design a proper waveguide with a compression driver that has a compatible phase plug design to really fix this issue.

Even Earl's fix will have at least 2 of these peaks so no matter what they are not going away .

So with that said this is why I don't worry about them. I am an end user hobby guy not a designer of transducers or waveguides. As bonkers as some curves look they sure can sound good which is the bottom line for me.

Rob
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Last edited by Robh3606; 27th March 2019 at 12:31 AM.
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Old 27th March 2019, 07:51 PM   #105
DualTriode is offline DualTriode  United States
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Quote:
Originally Posted by Robh3606 View Post
.....snip

So with that said .. I am an end user hobby guy not a designer of transducers or waveguides.

Rob
Rob,

End user you are not.

You are a hobby guy and avid experimenter.

Thanks DT
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Old 29th March 2019, 10:30 PM   #106
DualTriode is offline DualTriode  United States
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Hello,

While I am sorting the M2 waveguide and the PT H1010HF-1 waveguide. I am listening to 3-way + sub speakers; 2204 woofers, 2119H mids and 2344 waveguides + 2425H tweeters. I am guessing that the directivity is gently increasing with the 8 Inch cone mid-range and crosses over to match the DI of the 100 X 100 2344 waveguides. That is the goal, to be confirmed with test.

I really like what I am hearing. Dave Brubeck on original vinyl has a clearly dimensioned sound stage in my small listening room.

Thanks DT

Last edited by DualTriode; 29th March 2019 at 10:47 PM.
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Old 29th March 2019, 11:19 PM   #107
norman bates is offline norman bates  United States
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yes, excellent choice on the 2204.
Good to hear you have some enjoyment.

I imagine (and would bet) either pt is way better than the 2344, and I'm not positive.
I think the newest pt is even better.

M2 ?

My money is on the newer or older pt (so far as horn reflections especially at the mouth), but odds may be too close to call.

Norman
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Old 30th March 2019, 12:31 AM   #108
Robh3606 is offline Robh3606  United States
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Hello DT

Your set up sounds like a good choice of drivers. I basically did something very similar except I had a 10" as my mid and the directivity was matched at the crossover point and it sounded really good imaged great with an imperceptible transition between the 10 and the 2344. Curious to see how your comparison goes.

Hello Norman

Quote:
I imagine (and would bet) either pt is way better than the 2344, and I'm not positive.
You would be surprised how good an old design like the 2344 has held up. Especially crossing it over almost an octave higher than in the 4430. I still have my pair and one of these days I would like to get them running again. My favorite CD horn from that time.

Rob
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Old 30th March 2019, 06:57 AM   #109
norman bates is offline norman bates  United States
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True true, people love their 4430's.

Norm
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Old 1st April 2019, 08:24 PM   #110
homebuilder is offline homebuilder  United States
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Robh and TurnItDown:

Both of you have used the 2344a quite a bit, and still find it to be a good setup. In your opinion, how do the older 2425 drivers perform? A couple of other questions, which I hope are not too far off the path for this discussion:
1. You both comment on mids that mate up well with the 2344a...what about a 12" mid? Too big?
2. The compensation circuit 4430: does a constant directivity circuit in an electronic crossover such as the TDM brand do this same function for the 2344a?
3. Strictly for the purposes of experimentation, is there anything inherently wrong with putting a 2344a on top of a vintage speaker that has a wide range, efficient 12" woofer? I'm thinking of bypassing the stock midrange horn and crossover in that speaker, and using the 2344a, and a 2404. Not sure if the 12" woofer is a good fit. It is not going to go low in the current 3 cf box, but that can be augmented, of course.

Appreciate your input. Thanks!
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