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ClaudeJ1

Quarter Pie Bass Horn: Measured FR, How2Build, and Hornresp

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2 hours ago, noviygera said:

 

Here's that thread:

But looking at the response, it's not flat to 80hz. Looks more like a 130hz horn to me -- can't use that. Also, I have read somewhere that Tractrix is not optimal for midbass horn loading. In fact Bruce Edger pronounced it and I think I'll go along with that. Need hyperbolic or hyperbolic/exponential. So far the Q.Pie is my 1st choice. Like, ClaudeJ1 pointed out, I would also like to cross the subs below 80hz. But I would like to know what type of expansion Q.Pie uses.

Also is the Q.Pie 1/4space or 1/2space horn?

 

That looks like a small version of it. Wish I could find my measurements. Oh well whatever it measured it sounds awesome.

 

 

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21 hours ago, ClaudeJ1 said:

then it will be like an FH-1 with a higher cutoff frequency.

 

Yes.  I was quite surprised what that small change to the wood did to the upper frequency response.

Don't know what that does to the ability to sneak a 15" into the bottom of it, though.

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So has it really been 6 years?

Seriously?!

 

Well, 6 years ago this month I got my plywood ripped and only had one cross cut and the 11 degree angle cut remaining.  I had to pause for other projects and the plywood sat in the garage neatly stacked gathering dust and cobwebs.  Had 3 surgeries, got thin, beat cancer, ran a few 5K's, got fat again, got a couple of kids to college... been a busy time but I'm done waiting to get this done!

 

I had to dry fit the Crites cast just to see for myself that it fit.  I forgot that I was going to recess the cover but forgot.  Oh well, I don't care that it will add another 3/4". 

 

One issue is that I don't have the room anymore for them to lay flat.  I've got new subs placed such that I can only stand these upright in my room.  I've got plenty of depth so that won't be an issue.  I'll have an Elliptrac mid horn that I will basically have to sit on top of the access cover... or have the driver part of the frame resting on the cover and the horn sticking out and resting on the curve.  I'll have to support that somehow.  Assuming the woofer sounds good sideways, this is going to put my mid and tweeter too high.  I currently have the mid horn and tweeter sitting on top of the La Scala and it's a bit too high already.  I could benefit from sitting on a stool instead of a chair.  Not really my favorite choice.

 

I was thinking of building a bit of a frame (2x2 or thick dowel) to mount the mid driver in the bass horn close to the top but the mid driver would basically be shoved close to the vertical wall of the 31.75" board.  Really don't know how this would affect the bass horn blocking it partially like that. 

 

I'm staying passive with my DeanG Super AA networks so I'm also a bit concerned pulling the mid and tweeter forward too much from the bass horn.  I've got the tweeter mounted to the mid frame so that those two drivers are aligned.  Ideas? Thoughts? 

 

  

QP1wCrites.jpg

QP2.jpg

QP3.jpg

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That was a lot of developments in last six years.

I am glad that in all this you found the time to build Q-Pies.

 

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11 hours ago, parlophone1 said:

I stumbled upon this guy site.

He built the Qaurter Pies to try them against the closed sub.

 

https://mapoulin.wixsite.com/audiobym...

 

He writes about a lot of cabinet vibrations. Is this something to be concerned?

Most of the guys used the leftover lumber to put braces in, which I intentionally left to the guys building them. Also my original Qpies were the worst possible performers, with no braces, loss of lumber, 6" shorter horn, etc. yet they sounded great that way based on all the ears that heard them when I lived in Indy. Those who built the version 2's got way better performance, even without braces. You own the taste buds, and soup, and the salt shaker, but it's really a good soup to start with!

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18 hours ago, parlophone1 said:

I stumbled upon this guy site.

He built the Qaurter Pies to try them against the closed sub.

 

https://mapoulin.wixsite.com/audiobym...

 

He writes about a lot of cabinet vibrations. Is this something to be concerned?

His test still proved that horn had better TRANSIENT response vs. direct radiator. If he had use a Quad of 15's in a large ported box, he "might" have had better performance at 4 times the COST. Nice test on his part but it's incomplete.

 

In my case, I used it in a real room corners with an active crossover at 320 Hz. All room based PEQ was provided by Onkyo receiver 7 years ago, so it's an Apples and Oranges comparison at best. Those who have built them find their performance with similar PEQ's and Horn subs to be Excellent. For his particular GARAGE setup, it's not realistic in the real world of Musical listening. Besides, his other proposed "solutions" have completely different physical volumes. All I was trying to do was get 95% of the Klipsch MWMs sound while saving 40% of the floor space with a very easy build, which I accomplished. If someone wants to complicate things, they can design their own horn, but it won't be as simple as a Quarter Pie using a Klipsch K33!

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On 11/6/2020 at 12:17 AM, muel said:

I'm staying passive with my DeanG Super AA networks so I'm also a bit concerned pulling the mid and tweeter forward too much from the bass horn.  I've got the tweeter mounted to the mid frame so that those two drivers are aligned.  Ideas? Thoughts? 

I thought about doing what you are thinking, but I know for sure that Tromprof has his that way in his place and seems happy with the results. Near the low cutoff, if won't make much difference, but it "might could" make things a bit narrower dispersion above 300 Hz. But I'm sure if you simply TRY IT, you will like it!

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