KPT-1802-HLS vs three THT's

[jason str]

Phase problems exist anytime the same signal is sent to different cabinets.

 

The horn length alone can cause problems let alone using different drivers.

 

Why go looking for trouble, just use the same sub(s) throughout.

 

 

[ClaudeJ1]

Phase problems exist anytime the same signal is sent to different cabinets.

 

The horn length alone can cause problems let alone using different drivers.

 

Why go looking for trouble, just use the same sub(s) throughout.

Dr. Earl Geddes would disagree with you. He uses subs that are tuned differently for their placement in different parts of the room, but he's a brilliant scientist who has applied a huge amount of effort and patented technology to make it work.

 

I am not disagreeing with you since using twins is what I have done in the past and present. That being said so much of it depends on relative distances and whether or not you have different amplifiers for different gain level for each sub. Getting frequencies below 300 Hz. to behave well in any room is always a puzzle. Getting great sub bass (below 60 Hz. by my definition) can cost lots of dollars, time, cubic feet, placement options and amplifiers. So with all those other variables and dependencies, identical twins and quadruplets are not the only solution, but it does eliminate at least ONE of all the variables.

[ClaudeJ1]

Phase problems exist anytime the same signal is sent to different cabinets.

 

The horn length alone can cause problems let alone using different drivers.

 

Why go looking for trouble, just use the same sub(s) throughout.

I may sound contradictory, but the phase problems you speak of are a huge part of any ROOM, irrespective of horn length or subwoofer type. So THT's are not alone.

 

So a guy can build twin THT's and blend them with an 1802 successfully if he's willing to optimize their setup. All speaker setups have compromises.

Edited September 18, 2014 by ClaudeJ1

[CECAA850]

I may sound contradictory, but the phase problems you speak of are a huge part of any ROOM, irrespective of horn length or subwoofer type. So THT's are not alone

 

If you run the F-20's off of plate amps, you could at least have some flexibility with regards to phase adjustment.

[Thaddeus Smith]

something like the F20 with it's slim design can be stood against a wall, put under chairs, etc. 

 

it's still a fridge sized box, but your mind does get used to it and eventually your eyes stop wandering over to the big tall box in the corner.

[tromprof]

 

something like the F20 with it's slim design can be stood against a wall, put under chairs, etc. 

 

it's still a fridge sized box, but your mind does get used to it and eventually your eyes stop wandering over to the big tall box in the corner.

 

 

Also depends on what is around it. The F-20 is the small box on the bottom. Mine blend right in. 

[Thaddeus Smith]

ha, so true!

[jason str]

If you have the ability to adjust phase and delay on each subwoofer it would help but its still a band-aid repair on an issue that was created deliberately and could be avoided by simply using multiples of the same design.

[CECAA850]

Multiples of the same design that are at varying distances from the main listening position would give issues as well albeit slightly different issues.

 

Different subs can be integrated into a system and work well if you have the time, patience and calibrating equipment to do it.  Similar subs would definitely be easier though.

[Quiet_Hollow]

Dr. Earl Geddes would disagree with you. He uses subs that are tuned differently for their placement in different parts of the room, but he's a brilliant scientist who has applied a huge amount of effort and patented technology to make it work.

That's just it. He's a brilliant scientist privy to an understanding, well beyond the scope of practicality.

 

Let's be honest. It's a enough PITA to setup one subwoofer correctly, by someone who actually knows what they're doing..much less by someone with any doubts.

So a guy can build twin THT's and blend them with an 1802 successfully if he's willing to optimize their setup.

..which....would.....be completely impractical.

[Chris A]

Geddes is a bit of an arrogant personality based on my earlier discussions with him on DIYAudio.

 

He once proclaimed that modulation distortion in bass bins is inaudible...no kidding...he did, ignoring any links to PWK articles or any other more recent articles on the subject.  And he was dismissive about any discussion, i.e., he wasn't inquisitive on the psychophysics of the matter, and didn't take the references when presented to him.  I wouldn't take much of what he says as gospel for those reasons.  In fact, I'd steer clear of him.

 

He also takes credit for the quadratic throat (that is, a smoothly transitioning  throat) on conical horns--and he didn't invent it: it was apparently invented by another fellow (Charlie Hughes at Peavey got the patent).  This isn't an endearing quality by Geddes: taking credit for the design even though he only applied a math model to an existing design.  (By the way, the quadratic throat design doesn't work as well as advertised, I'm told by a fellow that I trust implicitly on this subject.)

 

YMMV.

 

Chris

Edited September 18, 2014 by Chris A

[ClaudeJ1]

 

FYI, sub 1 was slightly louder than sub2. I'm not sure what caused this, but it was the inside sub, and sub 2 was the outside sub. The measurements were taken in my shop. The closest wall is 60' away. The ceiling height is 24' at the eves.

 

Looking at your previous measurements and these pictures I believe you probably have several things that are adding up to the difference in the loudness of the two subs,

 

(1) Driver manufacture's variation of sensitivity could be part of the difference. 

(2) If not driven from the same amplifier channel then amplifier output power variation could be a factor also.

(3) sub1 being close to the LaScala could explain some of the gain difference as measured frequency increases.

 

 

miketn

 

I second the motion on all 3!

[ClaudeJ1]

Geddes is a bit of an arrogant personality based on my earlier discussions with him on DIYAudio.

 

He once proclaimed that modulation distortion in bass bins is inaudible...no kidding...he did, ignoring any links to PWK articles or any other more recent articles on the subject.  And he was dismissive about any discussion, i.e., he wasn't inquisitive on the psychophysics of the matter, and didn't take the references when presented to him.  I wouldn't take much of what he says as gospel for those reasons.  In fact, I'd steer clear of him.

 

He also takes credit for the quadratic throat (that is, a smoothly transitioning  throat) on conical horns--and he didn't invent it: it was apparently invented by another fellow (Charlie Hughes at Peavey got the patent).  This isn't an endearing quality by Geddes: taking credit for the design even though he only applied a math model to an existing design.  (By the way, the quadratic throat design doesn't work as well as advertised, I'm told by a fellow that I trust implicitly on this subject.)

 

YMMV.

 

Chris

Nah, I'm not taking Geddes as gospel, just as an example of assymetrical approach in woofer tuning and placement. Besides, now that I'm back in Mich. I'm only 20 minutes from his house and I understand he gives demos. I heard him speak at an AES meeting about 37 years ago, and I thought he was put offish then. I guess not much has changed personality wise. Don Keele told me he doesn't get along with Geddes either, so you have other opinions to back you up on that aspect.

 

What I found in listening, measurement, and having one THT and one Danley DTS-10 (briefly) in the same room, is that the position of my HEAD was far more critical. This persisted when I had twin DTS-10's front and back. The room simulation module in REW told me that the smoothest sub bass was with my head smack in the middle of the room, which was definitely proven with listening and measurements. That part of REW is a pretty good tool to get you going in the right direction.

 

When I modified some Heresy 1's into my "Ported Heretical Heresys" the measurements in my then bedroom exactly matched REW's room simulation, which made port to wall and head to speaker position quite critical below 300 Hz.

 

This is why I believe strongly that you can match up a couple of THT's or F-20's with the Klipsch 1802 sub if you are willing to work the REW simulation and your ears with good test music and Blue Rays to get it with and without LFE boost.

Edited September 23, 2014 by ClaudeJ1

[ClaudeJ1]

If you have the ability to adjust phase and delay on each subwoofer it would help but its still a band-aid repair on an issue that was created deliberately and could be avoided by simply using multiples of the same design.

Phase delays at those frequencies from the ROOM are in tens of feet, so it's not as critical as you make it out to be in single feet differences in the transducers. Either way it's would be very difficult and expensive for either of us to prove our arguments with data.

 

My simple advice to the OP would be TRY IT!!

 

I still believe that your listening position will compensate for any path length differences in the horn subs far better than adding more complexity with phase controls on plate amps, which I think are mostly crap compared to even a cheap digital Xover like a Behringer. If you ever measure a plate amp, you would most likely agree.

Edited September 23, 2014 by ClaudeJ1

[ClaudeJ1]

 

Dr. Earl Geddes would disagree with you. He uses subs that are tuned differently for their placement in different parts of the room, but he's a brilliant scientist who has applied a huge amount of effort and patented technology to make it work.

That's just it. He's a brilliant scientist privy to an understanding, well beyond the scope of practicality.

 

Let's be honest. It's a enough PITA to setup one subwoofer correctly, by someone who actually knows what they're doing..much less by someone with any doubts.

So a guy can build twin THT's and blend them with an 1802 successfully if he's willing to optimize their setup.

..which....would.....be completely impractical.

 

It would not be impractical from an economic standpoint or position options. The most "practical" in your terms would be a second 1802 in the middle of the back wall, listening position smack in the middle of the two, but that question was never asked.

Edited September 23, 2014 by ClaudeJ1

[Chris A]

If you are willing to forgo room gain, there is a much more interesting approach to placing subs in a room: http://www.avsforum....ad.php?t=837744

 

Here is the original article, translated from German by yours truly, the double bass array. All the longitudinal modes are simply swept clean by this intriguing approach.

 

(taken from:https://community.klipsch.com/index.php?/topic/136788-when-a-speaker-loads-the-room-what-is-it-doing/#entry1535167)

 

Chris

[derrickdj1]

I have used non-identical subs for a while.  I have also used identical subs in the same room.  The biggest thing I notice was phase problems around the tunning frequency of the subs when using non-identical subs.  With advance DSP, setting distances, and timing. these problems were fairly easy to overcome.  I have had has much troube integrating identical subs since the behave differently due to their locations.  Great results can be achieved with either configuration.  The key is to group the subs.  For example, I treat two sub A and A 1 as a single sub and B and B 1 as a single sub.  Then I integrate the A and B group of subs.  This is the technique that Mark Seaton of Seaton Submersive uses.

 

He also gain matches the subs to drive all amps the same.  In the small HT, the room is a dominate player in the mix when integrating identical or non-identical subs.  You can't discount Geddes method for 3 subs which I have also used.  Great results can be obtained by his method.

[DrWho]

Mostly loss of output from air leaks, even a pinhole size leak will cause loss.

 

Hogwash.

 

Take a perfect cabinet and then drill a 1/4" hole to create a leak and then measure the difference. I think you will be surprised.

 

I've built a lot of horns where I just place the pieces together before gluing and have measured <3dB differences - and you can certainly hear the whistling from all the leaks of the unglued prototypes.

[jason str]

On 9/23/2014 at 12:11 PM, DrWho said:

On 9/15/2014 at 2:33 PM, jason str said:

Mostly loss of output from air leaks, even a pinhole size leak will cause loss.

 

 

Hogwash.

 

Take a perfect cabinet and then drill a 1/4" hole to create a leak and then measure the difference. I think you will be surprised.

 

Bullshit

Been there, done that.

I was suprised on how much loss it causes from even a tiny leak around the driver, thats why expanding glue is used in the cabinet building process, to keep air leaks at bay.

Much also depends on where the leak is located.

Feel free to come by and i can simply remove a driver bolt from a completed cabinet for some testing, you're in the area.

 

I've built a lot of horns where I just place the pieces together before gluing and have measured <3dB differences - and you can certainly hear the whistling from all the leaks of the unglued prototypes.

Why bother testing a prototype horn with unglued rattling cabinet joints and whistling air leaks, if you measured a <3dB loss yourself why claim hogwash.

[jason str]

I have used non-identical subs for a while.  I have also used identical subs in the same room.  The biggest thing I notice was phase problems around the tunning frequency of the subs when using non-identical subs.  With advance DSP, setting distances, and timing. these problems were fairly easy to overcome.  I have had has much troube integrating identical subs since the behave differently due to their locations.  Great results can be achieved with either configuration.  The key is to group the subs.  For example, I treat two sub A and A 1 as a single sub and B and B 1 as a single sub.  Then I integrate the A and B group of subs.  This is the technique that Mark Seaton of Seaton Submersive uses.

 

He also gain matches the subs to drive all amps the same.  In the small HT, the room is a dominate player in the mix when integrating identical or non-identical subs.  You can't discount Geddes method for 3 subs which I have also used.  Great results can be obtained by his method.

 

I assume you're talking about conventional type subwoofers.

 

Personally i do not recommend mixing those either due to phase issues, by adding horn loading into the mix just adds to the complications.

 

If somebody absolutely has to blend subwoofers don't just hook them up to a plate amp and expect miracles to happen.

 

Phase cancellation is present as is delay complications in a horn loaded design, plan for the worst and hope for the best when mixing cabinets.