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ClaudeJ1

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

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22 hours ago, davewantsmoore said:

QPs are nothing special

 

Woah.  I just re-read this - and see how it could be misinterpreted.

 

I mean MY horns are nothing special.   As in the photos would look like any other, 'cept there is bracing in the mouth, they're made out of varnished marine ply.

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42 minutes ago, davewantsmoore said:

 

Woah.  I just re-read this - and see how it could be misinterpreted.

 

I mean MY horns are nothing special.   As in the photos would look like any other, 'cept there is bracing in the mouth, they're made out of varnished marine ply.

I took no offense to your comment at all once I realized the context of what you meant. But thanks for the clarification for the benefit of others.

 

Besides, I could never take offense from a guy who coined the phrase: "Velvet Sledgehammer" to describe their sound.

 

Peace, Love, Beatles!!

 

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I understood correctly... I knew you meant the look, but hadn't remembered your pics.

 

Bruce

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On 1/22/2017 at 2:34 AM, davewantsmoore said:

My synergy horns go down to nearly 200Hz ... where I crossover to QPs for the next 2 octaves.

 

Although I may move back to sealed boxes, as I can't really justify the space (I have a fairly small room = 300 sq. foot)

You can't go back. Velvet Sledge Hammers have totally spoiled you and you know it. LOL.

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Hello all, I haven't been here for a year or so. I am planning to do a QP bin using 15c drivers. The last time I looked here was a zip file named v2.2. Is this the most updated version after my absence? If there is an improved one, can anyone here point me to that link?

Your help will be appreciated.

 

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7 hours ago, Welborne said:

Hello all, I haven't been here for a year or so. I am planning to do a QP bin using 15c drivers. The last time I looked here was a zip file named v2.2. Is this the most updated version after my absence? If there is an improved one, can anyone here point me to that link?

Your help will be appreciated.

 

Plans are the same. The only change to consider is cutting a larger (about 21") corner reflector that could potentially improve the output at 400 Hz. It was suggested but never tried. If you with to try and measure/listen, you can always cut the larger corner board as an extra and temporarily put it in place with duct tape to see if there's any improvment. Otherwise, it's excellent as is.

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Oh one last question: I couldnt download the file but I have this pic. What I couldnt find is the thickness(type) of the woodply that is recommended?

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4 hours ago, Welborne said:

Oh one last question: I couldnt download the file but I have this pic. What I couldnt find is the thickness(type) of the woodply that is recommended?

 

I have used 3/4" plywood in mine.

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3 hours ago, tromprof said:

 

I have used 3/4" plywood in mine.

Affirmative.

 

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Hi Claude

Let me say ..... I'm really starting to hear what these horns are really all about! I now just have a simple minidsp on the bass only to EQ out the lift that these have in my room, strong in the 100-200hz range. I can now hear deep into these bass notes, lovely!!!

Anyway, because of this strong mid bass lift I've always want to try standing these up to see how they respond. Did it the other day and yes the response is flatter, photo below shows the 2 responses, first is vertical and the second trace is in the corner as designed. Level adjusted for clarity.

Listened to them vertically but was sure if it was any better.

Started thinking about the difference in responses and the layout of the bass to mid horn's.

In the flat position the bass and mid horns won't blend for until a distance from the openings.
What if I cut the top skin of the bass horn and angel it up from around the edge of the first part of the horn profile , around 17" from the back edge.
The horn will expand not only horizontally but vertically beyond the first part of the horn. One of my reasons for this is that it will allow the bass and mid horns to blend closer to the horn openings, plus the horn mouth volume will be larger. Lower Freq output???

Is this worth a try or will it completely screw up all your good design work??

Thanks20170306_134616.jpg
20170306_134456.jpg

Sent from my Moto G (4) using Tapatalk

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23 minutes ago, nzlowie said:

Anyway, because of this strong mid bass lift I've always want to try standing these up to see how they respond. Did it the other day and yes the response is flatter, photo below shows the 2 responses, first is vertical and the second trace is in the corner as designed. Level adjusted for clarity.

 

"Flatter" is not a particular good benchmark to use in this instance....   If anything you should be looking for "more like the predicated response" .... adjusting that for any effects from your room (eg. peaks and dips due to room modes).

 

I wouldn't both standing them up... I guess, is what I'm trying to say.

 

 

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So, what is the
"the predicated response"?
As mentioned earlier it's a bit hard to take them outside to measure and if I measure them at close range the response is even harder to deal with... At the moment I have them relitively flat with just a bit of low end lift and they sound pretty good. With any more lift they start to take over and dominate .



Sent from my Moto G (4) using Tapatalk

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Have a look in the first post/pages of the thread .... and there are some simulations of the horn.

 

  • If you're using a different driver - then they won't be valid for you.    If you let us know your driver we can make one for you.
  • Your measurements will also have your room imposed over the top.

 

Honestly, I don't think - unless you are running the QP horn up quite high in frequency ..... that it really matters which way you orient them ..... or that "integration" is a big issue.

 

As long as you have the mid-horn located less than 1/4 WL of the crossover frequency away from the centre of the QP mouth  (or even an edge of it).

 

 

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10 hours ago, davewantsmoore said:

Have a look in the first post/pages of the thread .... and there are some simulations of the horn.

 

  • If you're using a different driver - then they won't be valid for you.    If you let us know your driver we can make one for you.
  • Your measurements will also have your room imposed over the top.

 

Honestly, I don't think - unless you are running the QP horn up quite high in frequency ..... that it really matters which way you orient them ..... or that "integration" is a big issue.

 

As long as you have the mid-horn located less than 1/4 WL of the crossover frequency away from the centre of the QP mouth  (or even an edge of it).

 

 

I agree with this basic notion. I have always thought that standing them up was a good alternative and rotating the larger flare 90 degrees about the central axis would work well, but it would require more sawdust and re-attachment of the rotated section to achieve.

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I see.  If what is meant is just rotating the existing sections, and not changing their size and expansion substantially - then sure, that's fine.

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5 hours ago, ClaudeJ1 said:

I have always thought that standing them up was a good alternative and rotating the larger flare 90 degrees about the central axis would work well, but it would require more sawdust and re-attachment of the rotated section to achieve

One more thing.................if this were done, you would have opportunity to make it symmetrical as well.

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Laying them back down and just PEQ'ing the peak down at 160 Hz. with a lower Q, should clean it up quite nicely.

 

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That's about all the EQ I've got. Just thought if the standing up or opening up the mouth reduced this 160hz peak I thought we might get away with no eq..... Then just a simple low pass filter , all passive.


Sent from my Moto G (4) using Tapatalk

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On 3/11/2017 at 0:50 AM, nzlowie said:

That's about all the EQ I've got. Just thought if the standing up or opening up the mouth reduced this 160hz peak I thought we might get away with no eq..... Then just a simple low pass filter , all passive.


Sent from my Moto G (4) using Tapatalk
 

Keep in mind that your ROOM, relative to the horn position is doing this. IMHO, the ultimate feedback system to flatten and time delay a speaker is found in modern Digital Signal Processors, which are available from many vendors in many forms. Audyssey, YPAO, etc. come to mind, where the microphone sits where your ears are located and close the entire sound loop. When you have a super efficient/clean electro/acoustic transducers in place (horns from 100-110 db/Watt efficiency), the final "cleanup" is for the room fed back into the signal level compensation of the system. I have found no other approach that does as much to affect the sound quality so easily and cheaply. I'm using a Yamaha CX-A5000 Pre-Pro, which can be had for around $1,100 or less as a refurb or in the used marketplace, since their new 5100 unit merely adds Atmos capability. The key silicon component here is the "industry standard/state of the art" ESS Sabre DAC chip doing most of the work in concert with the rest of the team.

 

I use mine MOSTLY for 2-channel (with subs of course) listening with a single ended Class A power amp and have yet to find a better sounding combination in my 4 decades as an Audiophile.

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