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ClaudeJ1

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

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58 minutes ago, JLOP said:

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

Not to detract from Claude's work, but if you have working Altec 416's they are a valuable woofer that can be used in various ways. Over at DYaudio there are some highly acclaimed designs using that woofer (notably the Oaken cabinets, my spelling might be off). There are a number of choices.

 

Running a simulation is a good idea, but please keep in mind the the Altec 416 was produced for a number of years and not all versions have identical specifications. 

 

Good luck,

-Tom

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Hi Tom,

Thanks for feedback

I'd rather stay in the bass horn, I know the onken. I have large mid bass compression drivers Renkus Heinz SSD 5600 that could go somewhere in the 250/300 Hz with a large K402 similar horn adapted with a proper size throat or the renkus CD CBH250-6.

 

For the TS parameters, I can measure the Altec with Arta.

 

Jean-Louis

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It sounds like you have a good strategy. I also like bass horns. 

Good luck,

-Tom

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Alright, I've started building a set of Quarter Pies with 3/4" BB. Been on the fence for over 5 years and now have the room and time to make it happen! It's time to see what getting a "full horn" down to 50 Hz is all about. I'll be using the K-33 from my LaScalas and setting them on top of the Q-Pies, just as Claude has been suggesting for many many years. I wonder how many, if any LaScala owners have followed his suggestion?

 

I've cut the main pieces and pre drilled/counter sunk all the holes on #1 and #2, it has been very straightforward so far.

 

I haven't cut the flare pieces #7 and #8. The 11 deg angle will be easy, though I'm not sure how to cut the proper angle for where the flare pieces meet the sides. Bill Fitzmaurices jig plans include an acute angle jig, which will do the trick. Is there a simpler solution for those two cuts?

 

Will be updating soon and often.

 

Daniel

 

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14 hours ago, Ray_pierrewit said:

I haven't cut the flare pieces #7 and #8. The 11 deg angle will be easy, though I'm not sure how to cut the proper angle for where the flare pieces meet the sides. Bill Fitzmaurices jig plans include an acute angle jig, which will do the trick. Is there a simpler solution for those two cuts?

 

A jig works best and is the easiest. If you already have those cut for the 15 3/4 inch width, it is a bit harder, but using a jig to hold a 31 1/2 inch piece and do the angle cut, then rip each side flare from that.

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Had a good day, between being a stay at home father with three kids under 11 and building a set of Q-Pies. I ended up improvising a vertical crosscut jig for the table saw, which permitted me to get the acute angle cut I was enquiring about in my previous post. As far as I can tell, the fit will be almost perfect even if Claude has reassured me that a perfect fit isn't that critical to the overall performance.

 

I also fit and assembled the first three pieces (the large L and reflector). I made sure to keep it nice and square, glued and screwed every 4". I hope to work on this again tomorrow, I should be able to scrape a couple of hours away from the kids!

 

Question: should I build both channels at the same time or continue with the first until it's done?

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Well, I didn't update soon, nor often... too busy making sawdust and getting these things glued and screwed, I didn't even take any "build" pictures. I got them finished up last night and convinced my wife to help me shlep them into the studio. Someone earlier in this thread mentioned being surprised by the size of these horns once finished. AMEN to that!!! I knew going in they would be big, but once assembled and in place they make the LaScalas look like "normal" floorstanders. Claude had me speak into them before adding the drivers to see just how much it acoustically amplifies the male voice, boy does it ever. The kids were entertained listening to me make all manner of guttural noises into them.

 

I followed Claude and MustangGuy's dimensions exactly, everything fit just so nicely and the build was a real pleasure to assemble.

 

It was well past midnight by the time I installed the K-33 drivers and got everything hooked up, so my listening session was short and sweet. Here are my first impressions.

 

- I welcome the added 17" height to the LaScala's tweeters and squawker. I'm more often than not sitting in a drafting chair, which is quite a lot higher than a regular couch and the tweeters are essentially ear height. Having said that, in my listening chair which is lower, is also very pleasing.

 

- The added bass isn't subtle, and it sounds much better than my previous ported bass bin mods. I tried a couple of bass heavy tracks and the kick drum/double kick drum has more immediacy and slam. I also heard some very intricate bass guitar lines that are more palpable and clearly dig lower. The 140-160hz resonance of the LaScala seems to be a thing of the past, though I have no way of measuring with a mic. I ran some test tones and where I previously had an important hump in the 140-160hz range, it is now significantly and audibly reduced.

 

I will live with my system as is for now, it being for 2 channel music only. Subwoofers are definitely on my list of things to build sometime in the future. Building these was a great intro to cabinet building and I'm confident I can pull a subwoofer build with ease. I'm more than satisfied with the results so far!

 

A big shout out to Claude. This Q-Pie is such an elegant design solution for anyone with the room and ambition to get the most out of a bass bin, thanks Claude!

 

Daniel

Photo on 2020-07-01 at 3.49 PM.jpg

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I see that you used additional support panels in Q-Pies to hold LaScalas.

How far back those panels go into the Q-pies?

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NICELY DONE!

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On 7/1/2020 at 4:00 PM, Ray_pierrewit said:

I will live with my system as is for now, it being for 2 channel music only. Subwoofers are definitely on my list of things to build sometime in the future. Building these was a great intro to cabinet building and I'm confident I can pull a subwoofer build with ease. I'm more than satisfied with the results so far!

 

While it's not "my thing" to get other people to spend more money than they need (plywood, glue, and screws in this case) to get better sound, I do recommend an Eminence Kappa 15C if your want more midbass/midrange definition in the future, after building some Tapped Horn or Full Horn Subs. The 15C's represent best bang for buck in bass horns, so when you build subwoofers, you may want to consider that an eventual upgrade after adding the extra bass below 50-60 Hz.

 

Also, if you end up putting those subs underneath the Quarter pies (if you can't do one on front mid-wall and one on rear mid-wall as the better choice), you can then just try your LaScalas Upside down so things don't get too high for your ears!

 

I'm glad you have joined a select few of the worldwide builders of this horn, which works very well when "done right" as you have shown here! Congratulations on a very nice job. Keep us posted on further listening impressions and let me know if you need some suggestions about "best bang for buck" subwoofage and amps.

 

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20 hours ago, parlophone1 said:

I see that you used additional support panels in Q-Pies to hold LaScalas.

How far back those panels go into the Q-pies?

 

Yes, I added three braces per channel, they are 7" wide with 3 1/2" corner cutout, like the woofer mount piece. I used even more of the pre ripped lumber so there is even less wasted wood. 

 

6 hours ago, ClaudeJ1 said:

While it's not "my thing" to get other people to spend more money than they need (plywood, glue, and screws in this case) to get better sound, I do recommend an Eminence Kappa 15C if your want more midbass/midrange definition in the future, after building some Tapped Horn or Full Horn Subs. The 15C's represent best bang for buck in bass horns, so when you build subwoofers, you may want to consider that an eventual upgrade after adding the extra bass below 50 Hz.

 

Also, if you end up putting those subs underneath the Quarter pies (if you can't do one on front mid-wall and one on rear mid-wall as the better choice), you can then just try your LaScalas Upside down so things don't get too high for your ears!

 

I'm glad you have joined a select few of the worldwide builders of this horn, which works very well when "done right" as you have shown here! Congratulations on a very nice job. Keep us posted on further listening impressions and let me know if you need some suggestions about "best bang for buck" subwoofage and amps.

 

 

I think before adding any subwoofers to the fray, I'll need to learn how to take and interpret measurements. On this front I've borrowed a Umik -1 from a friend. Now I'll need to make sure that my Mac Os will support REW. I know that getting Sketchup to work on my computer was quite a task, I had to find a much older version. I'll find the appropriate REW measurement FAQ thread with questions as they arise. 

 

I'll take your advice, once again, and appreciate the Q-Pies as is for a while before considering my next move.

 

BTW, sub placement isn't an issue for me, I've got the luxury of total creative freedom in my space, it being an artist's studio after all!

 

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7 minutes ago, Ray_pierrewit said:

I added three braces per channel, they are 7" wide with 3 1/2" corner cutout, like the woofer mount piece. I used even more of the pre ripped lumber so there is even less wasted wood. 

I like this idea and what you have done to use up the material to make them even better. Way cool.

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How
Low do the pies go and a list
Of
Drivers that work well with it


Sent from my iPhone using Tapatalk

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7 hours ago, carlthess40 said:

How
Low do the pies go and a list
Of
Drivers that work well with it


Sent from my iPhone using Tapatalk

 

QPs will get down cleanly to 50 HZ, but I have found that 60 HZ seems ideal with  my F20 subs.

Since I have 5 QPs and 2 more straight QP variations I have a variety of drivers. I have EV 15L, Kappa 15c, and Klipsch K--33 in the system, though I try to pair like drivers.

Bob Crites also sells 15 inch drivers that would work fine too.

I know Claude prefers the Kappa 15c but I have found they all work very well and perform very similarly esp after running EQ. BTW all my speakers in this system are using either Xilica or Ashly processors.

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So I got my first good listening session in. Man, this really transforms my system to whole new level never yet experienced. New bass textures are really apparent and quite stunning really. I listened to some CDs that I've had for a couple of decades ranging from glitch electronic Pan American, to Hector Zazou, to Neil Young, to Brokeback, which is wonderful foray into acoustic stand up bass. Everything, and I mean everything that I've played has gained so much foundational impact that I believe I've reached my immediate audio goals... and for the price of lumber, screws, glue and paint. Everything cost me less than $400CDN, which has proven to be the best money I've spent since buying my LaScalas over 12 years ago for $800, which still represents my best bang for the buck purchase yet! Guys, this is a no brainer for whoever can afford the space and time to build them!

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Looks great!  Wish I had the space....

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On 7/3/2020 at 11:01 AM, tromprof said:

I know Claude prefers the Kappa 15c but I have found they all work very well and perform very similarly esp after running EQ. BTW all my speakers in this system are using either Xilica or Ashly processors.

I prefer the 15C for several reasons, which include the use of a SUBwoofer  below 60 Hz.. For no sub, the K33 has the "fattest bass" and it's easier to PEQ the top end at 400 Hz. (no increase in IM distortion) as opposed to trying to add more bass below 50 Hz. with higher IM distortion resulting. 

 

But the best reason of all is NO reconing of old, overpriced, used EV woofers that are 30 years old, or using 40 year old K33's if they were beat to hell in a Cornwall.

 

The 15C is the CHEAPEST driver that will do the job. If you prefer a K33, the Bob Crites woofer is a good one. No problems with brand new woofers whichever you choose!!!

 

You can't go wrong with any of them, since it's the HORN that does most of the work!

 

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On 7/1/2020 at 4:00 PM, Ray_pierrewit said:

The added bass isn't subtle, and it sounds much better than my previous ported bass bin mods. I tried a couple of bass heavy tracks and the kick drum/double kick drum has more immediacy and slam. I also heard some very intricate bass guitar lines that are more palpable and clearly dig lower. The 140-160hz resonance of the LaScala seems to be a thing of the past, though I have no way of measuring with a mic. I ran some test tones and where I previously had an important hump in the 140-160hz range, it is now significantly and audibly reduced.

I've been trying to convince LaScala guys to do what you did instead of adding reflex ports in a box underneath because you are eXtending the horn from about 2 1/2 to 5 1/2 feet long. So building a horn underneath gives you way more benefit than porting what becomes a direct radiator instead of a full horn.  BTW, there is NO  LaScala +7 db PEAK at140 hz. in the Quarter Pie's flat/exended curve. Consider all that stuff GONE.

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3 hours ago, ClaudeJ1 said:

 BTW, there is NO  LaScala +7 db PEAK at140 hz. in the Quarter Pie's flat/exended curve. Consider all that stuff gone.

 

I had a talk with the pal that recently bought new LaScalas. And they are pretty rare here.

According to him, he just had to try LaScalas at his home, and the only way to do it was to buy them.

All he had ever in his room were Magnepans.

 

Now, he kept LaScalas with him only for a very short time. The reason was the boxy sound from bass bins. Highs and mids to his ears were perfect. But that kicks out of bass bins he could not bear. Just went back to Magies.

 

Was that the peak at 140 Hz that you mentioned?

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