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ClaudeJ1

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

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Well it will get you to the right value then buy a Polypropylene cap. If it's 100 uF, you can get them from Parts Express, but don't spend too much on exotic ones when Daytons will do.

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Thank you ClaudeJ1.

This may be an older thread but the information will be valid as long as there are LaScala's  and Kappa 15C's left. My 1978 LaScala speakers have come back to me with Pioneer woofers, everything else is original. I was about to order 2 K33E but that is not going to happen now. Time to figure out if I can use the 1/4 pie here. My Velodyne 12" can't keep up!

C. J.

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2 hours ago, Crazy John said:

Thank you ClaudeJ1.

This may be an older thread but the information will be valid as long as there are LaScala's  and Kappa 15C's left. My 1978 LaScala speakers have come back to me with Pioneer woofers, everything else is original. I was about to order 2 K33E but that is not going to happen now. Time to figure out if I can use the 1/4 pie here. My Velodyne 12" can't keep up!

C. J.

The good news about Kappa 15C is the now lower price of $109 at Part Express, which used to be a sale price only. This is the best bang for the buck woofer in my Quarter Pie Design, out of the 3 that I simulated,  measured and heard. Really tight bass and a few extra decibels in the 400-600 hz. range, where you need to "hand off" to your chosen Klipsch midrange horn/driver. I still like the term "Velvet Sledgehammer" coined by our good buddy in Tazmania. You can get by without a sub if you build a Quarter Pie, and you can use the bass bin portion of your LaScala as a "spacer." Just run the woofer section of your AA network down the Quarter Pie and you are all set. You will never go back after experiencing 1+ octave or real horn bass below the LaScala's 104 Hz. horn cutoff since the Qpie is twice as long as the L.S. It's also flatter as well as more extended. Easy build, maximum enjoyment!

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Well, tried putting a cap series with the bass driver and it made a huge difference!!!

 

Red trace is the quarter pie with my second order input filter, blue trace is input filter plus 50uf series cap.

 

The result is a lot flatter but has killed the lower bass too much. Time to retry Minidsp .

Cap on bass.jpg 

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3 hours ago, nzlowie said:

Red trace is the quarter pie with my second order input filter, blue trace is input filter plus 50uf series cap.

Looks to me like 100 uF might do the trick (the reason I suggested a 50-100 range), or some value in between. I think you need a rising low bass response with any speaker (most do just the opposite) in order to get compensation in concert with the ISO Equal Loudness curves. I don't take those curves verbatim because they were derived from headphone listening tests and NOT from loudspeakers in rooms where low frequencies are more FELT than heard as the frequencies approach single digits.

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Thanks guys, I did try 100uf but from memory it didn't measure much difference. (Didn't save the trace for some reason).

Anyway having a break from the horn project for a while as I'm getting tired of adjusting and tweaking and not listening to music!

My DTQWT speakers are back in now, just hit play and enjoy! These don't have the same smoothness of mid range as the horns but have a beautiful refined "complete" sound and a really nice sound stage. With these I completely lose all sense of dimensions in my listening room.

Maybe in a few weeks I'll give them another try.

Cheers and thanks for your help along the way.

Dave

Sent from my SM-T800 using Tapatalk

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Hello Claude

I want to confirm my white QPs are doing well :-) I was trying not to change anything and focus on music. But one month ago I bought OpenDRC-DA8 by miniDSP and made a superb digital filters. Having time aligned all horns and linearising phase made the immersion even better.

 

However I stll use very gentle 6db filter on QP relying mostly on roll-off.

 

 

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1 hour ago, Mariusz_ said:

Hello Claude

I want to confirm my white QPs are doing well :-) I was trying not to change anything and focus on music. But one month ago I bought OpenDRC-DA8 by miniDSP and made a superb digital filters. Having time aligned all horns and linearising phase made the immersion even better.

 

However I stll use very gentle 6db filter on QP relying mostly on roll-off.

 

 

 

QPs are great. Time aligned QPs are better!

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On 12/28/2016 at 1:25 PM, Mariusz_ said:

Hello Claude

I want to confirm my white QPs are doing well :-) I was trying not to change anything and focus on music. But one month ago I bought OpenDRC-DA8 by miniDSP and made a superb digital filters. Having time aligned all horns and linearising phase made the immersion even better.

 

However I stll use very gentle 6db filter on QP relying mostly on roll-off.

 

 

Great news, thanks for sharing. I have my eye on Mini DSP products, especially this new family of boxes that only cost $349. Amazing for the low price.

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On 12/28/2016 at 2:42 PM, tromprof said:

 

QPs are great. Time aligned QPs are better!

Thanks for the plug................and the plug-in. LOL. Working on some new bass unit that is bastardized from old Peavey cabs and VERY cheap and easy bass, so to speak. Hope it works.

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If anyone in the SF Bay area wants to buy some Q-Pies... I will have mine ready this next week for sale. Mine are just painted black, and are priced at $150 (price of the woofers used)each if you buy all 3. PM me if you are interested.

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5 hours ago, ellisr63 said:

If anyone in the SF Bay area wants to buy some Q-Pies... I will have mine ready this next week for sale. Mine are just painted black, and are priced at $150 (price of the woofers used)each if you buy all 3. PM me if you are interested.

Photos of what you are using as replacements, and do they sound better or about the same in a smaller package?

 

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Photos of what you are using as replacements, and do they sound better or about the same in a smaller package?







 



I am building my own Synergy horns with Chris's help, completely out of MDF. They will be 2 ways with Ev dh1a DRI SRS and two woofers. I posted an early pic in Chris's synergy thread, and more pics in my home theater thread. We have one almost completed already. The next 2 will be made with the horn section removable so I can switch to the ones Chris is building if I like.

Sent from my SM-T550 using Tapatalk

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The cabinets are the same size as Chris's are, will take up less space, in my situation. I have no idea if it will sound better or not yet.

Sent from my SM-T550 using Tapatalk

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I would never sell something that works so well until I knew for sure that the replacement was better by measurement AND listening. In your application, space is not the problem. The main benefit of multiple entry horns is that the horn acts like a SINGLE DRIVER with reasonably wide bandwidth in a smaller space.............with proper Crosssover it can have great phase response also with constant directivity down to a few hundred Hz.

 

Your DTS-10's are great subwoofers, but they are best crossed in the 40 to 60 Hz. range.............the lower the better. This taxes the lower cutoff of whatever horn system you are using above it.

 

You probably know all this via Chris, so it looks to me like you are on your way to a potential improvement if done right.

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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)

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That's not really small. Does it have 8 ft ceilings? Pretty much the size I had my LS in at my previous house. I had thought about MWMs there, but remarried :ph34r:. Now we have a 21x23 room with 10ft ceilings. Can't wait to get refurbed LS back in operation there.

 

Do you have pics of your QPies? I'm sure they are somewhere back in this thread... :blink:

 

Bruce

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Yep - approx 8ft ceiling.   QPs are nothing special.  Quite elaborately braced inside the mouth.   Low pass response set to 24dB/octave @ 280Hz

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19 hours ago, davewantsmoore said:

Yep - approx 8ft ceiling.   QPs are nothing special.  Quite elaborately braced inside the mouth.   Low pass response set to 24dB/octave @ 280Hz

Yes, at ALL of the frequencies where the ROOM and not the horn dominates the response in your ears.

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