K-55-V used in a K402 horn?

[MarkKrochuck]

Hi all, I recently acquired a pair of K-55-V drivers for $100 and was wondering what options (besides the k400/401) I have for horns.

 

1. stick with k400/401 (anyone have some for sale)

2. This horn from (abc) or (xyz) is actually better, cheaper, etc.

3. What happens if the k-55-v is mated to a k402 horn?

 

thank you in advance.

[dtel]

I would say #1, don't know anything about others, it will not work on the 402 horn.

[Chris A]

19 hours ago, MarkKrochuck said:

3. What happens if the k-55-v is mated to a k402 horn?

Interesting. 

 

The problem is that the K-55 driver SPL dies above 6-7 kHz.  You could reuse the K-77 tweeters and put the K-55s on the K-402s with a 1" to 2" adapter, which would eliminate the collapsing polar midrange horn problem of the K-400/401 horns, but then the K-77 would be too far away from the centerline of the K-402 horn.  You could then move the K-77s into the mouths of the K-402s using a couple of straps across the mouth of the K-402 at 90 degrees to each other with the K-77 centered on-axis but at the mouth of the horn, and put lots of absorption material all over the reverse side of the K-77 tweeter to reduce the in-horn reflections of the K-77 assembly. Then you could use a DSP crossover to add enough delay to the tweeter to time align it to the K-402/K-55 driver.  The same DSP crossover could also time align the K-402/K-55/K-77 assembly to the bass bin. 

 

That would work...although it would be much easier (and probably cheaper in the long run) to buy good full range 2" compression drivers to put on the K-402s and use a DSP crossover (like a miniDSP 2x4 HD) to time align to the bass bin--just like a two-way Jubilee or KPT-942.  That would make a lot more sense, thus selling off the K-55s and the K-77s on ebay (which probably don't sound nearly as good as the 2" compression driver anyway).

 

Chris

[PrestonTom]

Regarding # 3 (K-55 on a a K-402)

 

I am always leery of using throat adaptors to mate mis-matched drivers and horn throats. 

In this case, there are so many good 2 inch drivers out there (some quite affordable), that using an adaptor really doesn't make sense. 

There is  another piece of the puzzle you have not told us: What are your intended crossover point(s) and will this be a two-way or three-way system? That issue should be solved first. 

 

Good luck,

-Tom

[dtel]

2 hours ago, PrestonTom said:

I am always leery of using throat adaptors to mate mis-matched drivers and horn throats. 

Kind of what I was thinking, it's like adding to the horn plus it was never intended for a design quite like that.

2 hours ago, PrestonTom said:

In this case, there are so many good 2 inch drivers out there (some quite affordable), that using an adaptor really doesn't make sense. 

That would be better than piecing mismatched parts. imo

 

And your last sentence is most important, it's like the first thing you need to know.

[geoff.]

I believe this is a knock off of an EV horn (that has a striking resemblance to TAD horn) that has a 600 hz cutoff but could probably do 500 with a steep slope. One member here does 400hz with a 48db active crossover (I think).

 

You would still need a tweeter.

 

Hey, your the dude with awesome CP-1 restoration!

 

Did you get the K-55s up in Owen Sound?!

 

They aren’t on my kijiji favourite’s list anymore, lol

[MarkKrochuck]

4 hours ago, Chris A said:

Interesting. 

 

The problem is that the K-55 driver SPL dies above 6-7 kHz.  You could reuse the K-77 tweeters and put the K-55s on the K-402s with a 1" to 2" adapter, which would eliminate the collapsing polar midrange horn problem of the K-400/401 horns, but then the K-77 would be too far away from the centerline of the K-402 horn.  You could then move the K-77s into the mouths of the K-402s using a couple of straps across the mouth of the K-402 at 90 degrees to each other with the K-77 centered on-axis but at the mouth of the horn, and put lots of absorption material all over the reverse side of the K-77 tweeter to reduce the in-horn reflections of the K-77 assembly. Then you could use a DSP crossover to add enough delay to the tweeter to time align it to the K-402/K-55 driver.  The same DSP crossover could also time align the K-402/K-55/K-77 assembly to the bass bin. 

 

That would work...although it would be much easier (and probably cheaper in the long run) to buy a good full range 2" compression drivers to put on the K-402s and use a DSP crossover (like a miniDSP 2x4 HD) to time align to the bass bin--just like a two-way Jubilee or KPT-942.  That would make a lot more sense, thus selling off the K-55s and the K-77s on ebay (which probably don't sound nearly as good as the 2" compression driver anyway).

 

Chris

I was thinking about cutting a square hole in the k402 and inserting a tweeter

[MarkKrochuck]

1 hour ago, geoff. said:

I believe this is a knock off of an EV horn (that has a striking resemblance to TAD horn) that has a 600 hz cutoff but could probably do 500 with a steep slope. One member here does 400hz with a 48db active crossover (I think).

 

You would still need a tweeter.

 

Hey, your the dude with awesome CP-1 restoration!

 

Did you get the K-55s up in Owen Sound?!

 

They aren’t on my kijiji favourite’s list anymore, lol

Could have been the guy, I am not sure. He was trying to sell them for $160

[PrestonTom]

16 minutes ago, MarkKrochuck said:

I was thinking about cutting a square hole in the k402 and inserting a tweeter

Please tell me that you are kidding ....

[MarkKrochuck]

33 minutes ago, PrestonTom said:

Please tell me that you are kidding ....

Choppy choppy

[Dave A]

If you are good at doing these things and have a well thought out plan like Chris A did whack on those 402's. Otherwise leave them alone and find a good 2" driver and be done with it. I cant believe a cobbled together K-55 + K-77 would ever do anything worthwhile on a 402 horn. Out of morbid curiosity though if you do chop on those get some pictures and post them and the results here.

[MEH Synergy]

Morbid curiosity killed the cat (or in this case the 402)

[Dave A]

No doubt and I hope he does not do this. Playing with a B&C DE1085 driver lately that is really good out to 20khz and crosses at 650hz just fine. Not an 1132 but this silly thing does 280 watts and i am thinking of trying it out on those 415 bass bins.

[MEH Synergy]

4 minutes ago, Dave A said:

No doubt and I hope he does not do this. Playing with a B&C DE1085 driver lately that is really good out to 20khz and crosses at 650hz just fine. Not an 1132 but this silly thing does 280 watts and i am thinking of trying it out on those 415 bass bins.

Looks like winner winner, chicken dinner 

[MarkKrochuck]

1 minute ago, Westcoastdrums said:

Looks like winner winner, chicken dinner 

 

6 minutes ago, Dave A said:

No doubt and I hope he does not do this. Playing with a B&C DE1085 driver lately that is really good out to 20khz and crosses at 650hz just fine. Not an 1132 but this silly thing does 280 watts and i am thinking of trying it out on those 415 bass bins.

What do you run below 650hz?

[Dave A]

1 minute ago, MarkKrochuck said:

 

What do you run below 650hz?

What I am thinking of using them with are some 415 klipsch bass bins. https://www.klipsch.com/pro/cinema/behind-the-screen/2-way

[Chris A]

11 hours ago, MarkKrochuck said:

I was thinking about cutting a square hole in the k402 and inserting a tweeter

The problem with MEH (multiple entry horn) designs is that you really can't cross any higher than 2 kHz from a midrange to a tweeter driver--because you can't get the two drivers close enough together around the throat of the horn to get the midrange horn ports within 1/4 wavelength of the tweeter port at the crossover frequency. 

 

For a K-55/K-77 combination, the crossover frequency needs to be ~4.9 kHz.  The 1/4 wavelength distance at that frequency is 13584 in/sec divided by (4900*4) = 0.69 inches.  That's the maximum axial separation distance of the horn adapter ports of the K-77 tweeter throat (without attached horn) to the K-55 driver port, as measured inside a 1" to 2" K-402 horn adapter.  That's pretty close. 

 

If you tried to cross over at an octave lower frequency (2.4 kHz) that would give you double the distance between the drivers (1.39 inches) but now you're risking blowing the K-77 tweeter diaphragm--which really doesn't do nearly as well at that lower crossover frequency and it also doesn't sound very good.

 

It's much better to use a 2" compression driver with both the midrange and tweeter diaphragms built in--like a BMS dual diaphragm driver, and bi-amp the two diaphragms such that the extra one wavelength of path length between them at ~6 kHz crossover frequency can be taken out by a DSP crossover.  Then you've got TAD TD-4002-like performance out of the driver/horn in a two-way configuration. 

 

Whatever you do, you're really going to need the flexibility of a DSP crossover instead of the passives found in stock Heritage loudspeakers to time align the drivers and to take out the SPL response variations that you will see due to the controlled directivity K-402 (or K-510) horn, i.e., you have to EQ the resulting SPL response flat again.  You'll need to measure the SPL and time response of the drivers to do this.  A calibrated microphone ($95) and REW can facilitate this.

 

Chris