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ClaudeJ1

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

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On 1/24/2019 at 1:31 PM, Mrscy said:

 

I am ready to build arectangular version,

Do I add a 31.75" panel above the rear chamber or a 48" panel parallel to #3?

If I put a 48" panel parallel to panel #3 there will be 2 corners, must the simulation be in 0.5pi or 1pi?

 

Thank you in advance.

I don't understand your question. All I said was you can omit the radius. Also I did this thing 6 years ago, but I'm glad you have interest. They do work very well. I made a crude Photoshop modification to the original photo, showing how they should be stacked. If you just omit the radius, you will havea 48x48x34" tall double Quarter pie. 

QPstacked.jpg

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1684537760_cornersubrectangular1.thumb.jpg.99522af0b2d028e2ddfed471a1f70160.jpg

 

Hope the drawing makes ense, do I add the 31.75 x15.5" or the 48x15.5" panel to make it a 48x48?

 

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On 1/24/2019 at 1:31 PM, Mrscy said:

 

All yo uneed is a 1 1/2 to 2" dowel rod or 2x2" corner brace as in the RED Circle. Otherwise the #1 and #2 pieces are 48x48, with no radius. You don't have to enclose the 2 sides at all. It may look weird to some but will work just fine as a square. 

 

 

QpieSquareweb.jpg

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Not sure how to tag a user, but this message is intended to be read by #ClaudeJ1

 

I've read and reread this thread several times and am nearer than ever to embark on building some QPies for my listening room/artist's studio. I intend on sitting my Lascalas on top of them. They are currently sitting atop the bassbin mod bins I built several years ago. Everything sounds great, the mod certainly help with the low end, though I do find the bass bins to be an eyesore. The QPies already have an edge in that regard, I find them quite elegant and they would blend well with my polycylindrical  diffusors lining my walls. I'm also compelled by the thought of a fully horn loaded system and would rather not integrate subwoofers for now. I've source my baltic birch and am working on the budget, which should permit me to build these in the coming months.

 

I've also followed, with great interest, the SMWM thread and share Dave's intent not to add any subwoofers for now. Having said that, I saw that my BB supplier also sells 5'x5' sheets and they are very reasonably priced. Would it be possible, or indeed desirable, to build a set of 5' sq QPies, thus lengthening the horn length? Would it add much to the bottom end? Would my K-33 woofers work in such a context? Would my current xovers (AA) need any sort of modification to have a passive network? Thoughts?

 

I've got the room (16'w x 26'l x 10' h), it wouldn't add much to the cost nor the difficulty of construction. I'd be willing to give it a go if you'd be kind enough to think about it and model au besoin.

 

Thanks for all of your contributions to this forum!

Daniel

Photo on 2019-02-20 at 9.13 AM.jpg

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Question about your panels... are they open on the half moon part of each one, and is there anything stuffed behind them.

Sent from my SM-T550 using Tapatalk

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6 minutes ago, Ron E said:

Question about your panels... are they open on the half moon part of each one, and is there anything stuffed behind them.

Sent from my SM-T550 using Tapatalk
 

 

Yes, they are open and there isn't anything stuffed behind them for the time being. They were installed after having read about a similar approach by PWK in a Dope from Hope article. I needed to cut reverberation in my studio, which was out of this world. Before installing them I tried the clap test and I swear it sounded like a spring going back and forth. Now when I clap in the listening area, it's sharp and decays quickly. It was very cheap and effective in my situation.

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How thick is the material you used... I am also thinking of doing this. Is it bendable plywood.

 

 

Sent from my SM-G935V using Tapatalk

 

 

 

 

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Thanks, I will have to see if it is available in Mexico. what did you use for the mounting of each side...a piece of wood with angles cut to slide it in?

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So this stuff is just for bouncing the sound around the room away from you?


Sent from my iPhone using Tapatalk

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20 hours ago, Ray_pierrewit said:

Not sure how to tag a user, but this message is intended to be read by #ClaudeJ1

 

I've read and reread this thread several times and am nearer than ever to embark on building some QPies for my listening room/artist's studio. I intend on sitting my Lascalas on top of them. They are currently sitting atop the bassbin mod bins I built several years ago. Everything sounds great, the mod certainly help with the low end, though I do find the bass bins to be an eyesore. The QPies already have an edge in that regard, I find them quite elegant and they would blend well with my polycylindrical  diffusors lining my walls. I'm also compelled by the thought of a fully horn loaded system and would rather not integrate subwoofers for now. I've source my baltic birch and am working on the budget, which should permit me to build these in the coming months.

 

I've also followed, with great interest, the SMWM thread and share Dave's intent not to add any subwoofers for now. Having said that, I saw that my BB supplier also sells 5'x5' sheets and they are very reasonably priced. Would it be possible, or indeed desirable, to build a set of 5' sq QPies, thus lengthening the horn length? Would it add much to the bottom end? Would my K-33 woofers work in such a context? Would my current xovers (AA) need any sort of modification to have a passive network? Thoughts?

 

I've got the room (16'w x 26'l x 10' h), it wouldn't add much to the cost nor the difficulty of construction. I'd be willing to give it a go if you'd be kind enough to think about it and model au besoin.

 

Thanks for all of your contributions to this forum!

Daniel

Photo on 2019-02-20 at 9.13 AM.jpg

The QuarterPie Horn is TWICE as long as the LaScala horn and much flatter response from 50-400 Hz. while only taking up an extra foot from the corner and using all the space right into the corner (unlike all the wasted space behind the LaScala). Yes, the K-33 woofer works very well in a Qpie, if you want more bass and less midrange handoff to the K400. Otherwise, going with a Kappa 15C is the best sounding driver overall and a very good value. Just do it. It will amaze you!! So yes, get rid of the Problematic Bass Reflex compromise, build the Qpies, and pull the drivers out of the LS' and put them in the Qpie cabinet, using just the top end of the LaScala. And yes, the AA network is just fine. The amount of bass definition and impact from the Qpie will absolutely stagger your senses, using the very same K33 drivers, I guarantee it.

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1 hour ago, ClaudeJ1 said:

The QuarterPie Horn is TWICE as long as the LaScala horn and much flatter response from 50-400 Hz. while only taking up an extra foot from the corner and using all the space right into the corner (unlike all the wasted space behind the LaScala). Yes, the K-33 woofer works very well in a Qpie, if you want more bass and less midrange handoff to the K400. Otherwise, going with a Kappa 15C is the best sounding driver overall and a very good value. Just do it. It will amaze you!! So yes, get rid of the Problematic Bass Reflex compromise, build the Qpies, and pull the drivers out of the LS' and put them in the Qpie cabinet, using just the top end of the LaScala. And yes, the AA network is just fine. The amount of bass definition and impact from the Qpie will absolutely stagger your senses, using the very same K33 drivers, I guarantee it.

 

I'm afraid you may have missed the crux of my previous message which was: I'm getting ready to build the QPies, only I was wondering if I would gain much by increasing it's size, much like Dave's SMWM, by using a 5' x 5' sheet of BB?  Thanks for responding Claude!

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4 hours ago, Ray_pierrewit said:

 

I'm afraid you may have missed the crux of my previous message which was: I'm getting ready to build the QPies, only I was wondering if I would gain much by increasing it's size, much like Dave's SMWM, by using a 5' x 5' sheet of BB?  Thanks for responding Claude!

Thanks for clarifying. When I designed Dave's SuperMWM, the length was the primary consideration to match the K-43 driver in the model. When we added the extra Height, strictly for less scrap lumber, by changing the dimensions to optimally utilize the 60" dimension of the RAW BB, we got more efficiency out of it, along with a smoother response in the HornResp model. I won't get to hear it until January 2020, since he's 10 hours south of me. 

 

Let me try and do the same to the Qpie and see what I get. I'll get back to you.

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OK, so here's the tall version, same as the SMWM in height. You get about 2 db more output between 50-80 Hz. with a K33 woofer. But you will still need a good tapped horn sub below 50 Hz.!!

 

QPIEvsTallQpie.jpg

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Does that include making it 5' per side instead of 4'?

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Yeah, I'm more curious about building a 60" x 60" (rather than 48" x 48")...

 

Edited by Ray_pierrewit
clarification

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4 hours ago, Ray_pierrewit said:

Yeah, I'm more curious about building a 60" x 60" (rather than 48" x 48")...

 

OK, so you want the same "L" type to fit in a corner? So it would be a hybrid between a Super MWM and a Quarter Pie to fit perfectly into a corner then. OK. This means the horn will be LONGER and go LOWER than 50 Hz. Got it.

60vs48QpieK33.jpg

As you can see, by going with 60" Baltic Birch, you lengthen the horn from 5.5 to 6.88 feet, which gets you down to 41 Hz. instead of 51 Hz. Cutoff with a K33. NICE!!

This is also the taller version, about 21" vs. 17" so you get a tiny bit more output out of it.

Edited by ClaudeJ1
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I might just be crazy enough to go for it! The winters in Canada are long enough to merit a worthwhile project like this. I know you, Claude, will always prone bottomless bass with several tapped subwoofers, but I'm pretty sure I'd be happy enough with 41hz for my music only system. I'll PM you when as I get nearer to realizing this dream. Thanks again for your input.

 

Daniel

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13 hours ago, Ray_pierrewit said:

I might just be crazy enough to go for it! The winters in Canada are long enough to merit a worthwhile project like this. I know you, Claude, will always prone bottomless bass with several tapped subwoofers, but I'm pretty sure I'd be happy enough with 41hz for my music only system. I'll PM you when as I get nearer to realizing this dream. Thanks again for your input.

 

Daniel

Keep in mind that the "core section" made of #7, 8, 9, 10 numbered pieces will be proportionally longer to maintain the same "round the corner reflector" plan dimension of 15.5 inches while also making the final section longer and with a bigger radius. This new "Super Qpie" will be pretty sweet down to covering 99% of music without a subwoofer. Even my original, much shorter Qpie had adequate output below 50 Hz. to make a sub mosty "icing on the cake." The one you build will be the cake and the icing, both! LOL.

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