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ClaudeJ1

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

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9 hours ago, Marvel said:

I know this will probaby cause an argument...

No argument here. A full horn totally trounces a LaScala with bass reflex mod, since the group delay issues are clearly audible. But the LaScala bass section doe make a terrific inactive SPACER between the top section and the Quarter Pie, however! All the while enjoying FULL Horn bass from the Qpie!! LOL.

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On 10/30/2019 at 5:44 PM, tromprof said:

The Quarter Pie horn is really a wonderful design (thanks Claude!). I really don’t see much benefit in adding a foot to the original design just to get 10HZ. Regardless of size, you are going to want a good sub (I have a pair of  Cinema F20 subs) and if implemented correctly seamlessly hand off to the QPs. Bigger isn’t always better, just harder to move.

I agree with your use of a sub to get the last lower octave, since the excursion requirements of the 20-50 Hz. range is HUGE. Doing it your way lowers IM distortion quite a bit................keeping it clean while shakin' yer bootie with the sub is a great thing!

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I've read the first 7-8 pages as well as the last 5. I'm sold on the easy to build part and great sound. Space is a bit of an issue so no 5-footers for me. Can someone please post a link to latest/most accurate plans? Great fall project.

 

Also if buying drivers new (no La Scala parts laying around). What is the best path for a 2-way system? I'm interested in the mid handoff more than absolute lowest dBs.

 

Thanks!

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On ‎11‎/‎1‎/‎2019 at 8:34 AM, rplace said:

I've read the first 7-8 pages as well as the last 5. I'm sold on the easy to build part and great sound. Space is a bit of an issue so no 5-footers for me. Can someone please post a link to latest/most accurate plans? Great fall project.

 

Also if buying drivers new (no La Scala parts laying around). What is the best path for a 2-way system? I'm interested in the mid handoff more than absolute lowest dBs.

 

Thanks!

 

@ClaudeJ1 Anyone with a little help here? Specifically 48" version, taller height if that helps as I think I read about two different heights, no?

 

I'm thinking I'd like to hear the difference between my Open Baffle H frames as bass bins for my big 2-way horns.

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1 hour ago, rplace said:

 

@ClaudeJ1 Anyone with a little help here? Specifically 48" version, taller height if that helps as I think I read about two different heights, no?

 

I'm thinking I'd like to hear the difference between my Open Baffle H frames as bass bins for my big 2-way horns.

You can just go buy the JPG file with dimensions in the very first post. Or use the 3D 2.2 plans from MustanGuy.

 

I still think the best and cheapest woofer driver for the Quarter Pie is the Eminence Kappa 15C at only 100 bucks each to so for brand new drivers (just ask the undisputed KING of the Qpies, TromProf about this, he's tried them all and came back with my recommendation). Baltic Birch is the best lumber, but if you want to save a few buckolas, then go with Arauco plywood, or you can totally cheap out (forgive me DaveA) you can use MDF. The 48" version has been optimized for least amount of scrap plywood and the fact that ALL the cuts are RIP cuts, once you have your table saw fence all set up, it's LITERALLY "Let 'er RIP for all your assembly pieces.

 

You then just have to do the 2 and 2  11 degree angle cuts as a "trim off the excess lumber." PL 3 glues expands and forgives "the construction sins of inexperience" if this is the case here. Bottom line is the Nike slogan "Just DO IT" fully applies here. You will not regret it. It's the best use of lumber and space with very few compromises to get the sound of a FULL HORN LOADED BASS that will give all other options a run for their money!!

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Forgot to add that in the right room, you won't even need a sub for most music if your Cabin Gain happens to be sympathetic and your are sitting in the right sweet spot. The ROOM dominates the bass below 300 Hz. as you know, but we all need to be reminded each time.

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3 hours ago, ClaudeJ1 said:

Eminence Kappa 15C

 

Any idea how the Eminence Alpha 15 might perform? I have two just laying around. Just curious is all, if the Kappa is the better I can't see cheeping out for $200 bucks if it is the best you have found.

https://www.parts-express.com/eminence-alpha-15a-15-driver--290-407

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14 hours ago, rplace said:

 

Any idea how the Eminence Alpha 15 might perform? I have two just laying around. Just curious is all, if the Kappa is the better I can't see cheeping out for $200 bucks if it is the best you have found.

https://www.parts-express.com/eminence-alpha-15a-15-driver--290-407

Terrible choice for the Alphas. I have 4 of those myself and they are great for Open Baffle, but nothing else. Trust me on this. My friend used 16 of them for his award winning Open Baffle, but they are totally wrong for horns.

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@ClaudeJ1 can I get an explanation of why the woofer mount piece #9 has the oval cut out and the 4 corners trimmed back? Not doubting the design just curious as to the why behind it. If the corners were square I'd think a more air tight fit. If the hole was as round as the drivers metal surround (like a cornwall in motor board) I'd think more sound getting out easier or less restrictive path for the sound. I'm sure it has something to do with it being a horn, but can't really figure out how that helps.

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On ‎11‎/‎7‎/‎2019 at 2:27 PM, rplace said:

@ClaudeJ1 can I get an explanation of why the woofer mount piece #9 has the oval cut out and the 4 corners trimmed back? Not doubting the design just curious as to the why behind it. If the corners were square I'd think a more air tight fit. If the hole was as round as the drivers metal surround (like a cornwall in motor board) I'd think more sound getting out easier or less restrictive path for the sound. I'm sure it has something to do with it being a horn, but can't really figure out how that helps.

 

A week later and nobody feel like splainin?

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23 hours ago, rplace said:

 

A week later and nobody feel like splainin?

I don't know if this is exactly the same thing but check out this 11 year old thread about building the MWM bass bins:  

Having the corners cut off allows for more back chamber volume.

 

As for the slot opening here is another old thread:

"In my view, the restriction slot is there to form a chamber in front of the diaphragm. Classic theory is that it is possible to bump up the response at, here, 400 Hz, if you have a chamber in front of the diaphragm. The front chamber volume "spring" forms a resonance with the mass of the diaphragm" ;

 

Not saying I understand it - here is another post from that same thread:

 

 

 

Edited by tom1066
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On 11/7/2019 at 2:27 PM, rplace said:

@ClaudeJ1 can I get an explanation of why the woofer mount piece #9 has the oval cut out and the 4 corners trimmed back? Not doubting the design just curious as to the why behind it. If the corners were square I'd think a more air tight fit. If the hole was as round as the drivers metal surround (like a cornwall in motor board) I'd think more sound getting out easier or less restrictive path for the sound. I'm sure it has something to do with it being a horn, but can't really figure out how that helps.

Did not get a notice of your question. Basically the Four 45 degree cut corners make the two triangular areas part of the Back Air Chamber Volume, even though mechanically, they are forward of the woofer throat sections, they are actually, ACOUSTICALLY, part of the back air chamber volume, which drops the peak down a bit at the horn cutoff frequency of about 51 Hz.

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On 11/14/2019 at 2:02 PM, rplace said:

 

A week later and nobody feel like splainin?

I am not "nobody." I am the sole creator the Quarter Pie Horn. I extrapolated the Klipsch MWM with a clear thought process and simulation,  over several months and many iterations of virtual design experimentation, and did not publish it until I actually built 2 of them and showed the measurements, along with the benefits.

 

It's not perfect, nothing is (even the Klipsch Designs have their anomalies) but it's a darn good sounding bass horn using the least amount of floor space possible and efficiently using up the air space afforded by a corner (as opposed to a LaScala totally wasting that dead air space). From "the sweet spot," my Quarter Pie (MWM derived) horn totally STOMPS a LaScala if you can handle the lumber sticking out into the room an extra foot.

 

Even though I have been helping people free of charge for over 13 years on this forum, I do have a life outside of it. over 6,000 posts should prove that and need no further explanation.

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12 hours ago, ClaudeJ1 said:

 over several months and many iterations of virtual design experimentation, and did not publish it until I actually built 2 of them and showed the measurements, along with the benefits.

FYI, the modified dimensions that were designed to was less lumber, as opposed to my original build, which was 45" instead of 48" (leftover from a LABhorn I never built), the results from v. 2.2 are actually BETTER than my measurements suggest. This is because the horn ended up as 1/2 of a foot longer, which lowered the cutoff frequency by several Hertz.

 

Again, ALL loudspeakers need a subwoofer. I just heard the best speaker/amplifier system I ever heard about 10 days ago, in a super tweaked high end dealer's demo room, but that system cost $750,000.00. So try comparing THAT.

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13 minutes ago, ClaudeJ1 said:

 

 

Again, ALL loudspeakers need a subwoofer. I just heard the best speaker/amplifier system I ever heard about 10 days ago, in a super tweaked high end dealer's demo room, but that system cost $750,000.00. So try comparing THAT.

Do tell, what did you listen to?  

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18 minutes ago, Shiva said:

Do tell, what did you listen to?  

The unveiling of the Wilson Audio Chronosonic XvX with their top of the line Subwoofer. The R and L channels drive by Dan D'Agostino's Monoblocs that cost $250,000/pair, speakers and Sub at about $500,000 in a really good room. Also one of the test songs was an LP playing on a $500,000 turntable, which brought the price tag fo $1.2 Million. It's most refined loudspeaker setup I ever heard. 3D imaging, micro detail, impact, etc. They clain 5 microsecond time alignment.

 

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1 minute ago, ClaudeJ1 said:

The unveiling of the Wilson Audio Chronosonic XvX with their top of the line Subwoofer. The R and L channels driver by Dan D'Agostino's Monoblocs that cost $250,000/pair, speakers and Sub at about $500,000 in a really good room. Also one of the test songs was an LP playing on a $500,000 turntable, which brought the price tag fo $1.2 Million.

I had a feeling it was going to be a Wilson system. i have seen those speakers on display in a few youtube vids. Obviously,  the Wilson brand is not just good marketing.  

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1 minute ago, Shiva said:

I had a feeling it was going to be a Wilson system. i have seen those speakers on display in a few youtube vids. Obviously,  the Wilson brand is not just good marketing.  

I got one of their last brochures on the way out. As a commercial photographer, I'd say the brochure cost $50 to make, it's better than most photography books my pictures have been in. First class all the way.

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Hi Claude

 

First post here as I am fascinated by your build that I find particularly interesting for its limited height, thus medium driver can be at ears’ level contrarily to the Altec VOT A7 I am currently using with ALTEC 416 8C

 

Do you think the 416 can be used ? Also, I am not familiar with hornresp. Would you mind publishing the screen with input parameters so that I could safely make some sims without mistakes ? Thank you so much

 

Jean-Louis, Luxembourg

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