KPT-1802-HLS vs three THT's

[mustang guy]

OK, I should have better things to do with my time than draw, but it's been a long weekend.  

 

Check this out. Its a KPT1802 block next to 3 24" wide THT's blocked together. 

 

 

Which sub would win the battle? Real quick, here are some specs:

 

KPT-1802: 

FREQUENCY RESPONSE: 26Hz-240Hz +/- 3dB; f10: 21Hz-500Hz -10dB (3M, Half-space anechoic)

SENSITIVITY: 100 db @ 2.83V (SPL at 1M, half-spaced anechoic with 2.83 volts input)

POWER HANDLING: 1100W (93V) 26Hz-250Hz (AES standard, continuous pink noise, 6dB peaks)

MAXIMUM CONTINUOUS OUTPUT: 130db 25Hz-250Hz (Calculated at 1M half-spaced at power handling power input)

NOMINAL IMPEDANCE: 6 ohm (4.5 ohm min. @100 Hz)

ENCLOSURE: Horn-loaded vented system (US Patent 5,898,138)

ENCLOSURE MATERIAL: ¾" Plywood

TERMINALS: Barrier Strip

DIMENSIONS: 72" (182.9cm)W x 48" (121.9cm)H x 31" (78.7cm) D

WEIGHT: 300 lbs (330 lbs shipping)

RECOMMENDED EQ: PEQ f=70 Hz, Q=6, Gain=-6 dB

RECOMMENDED HIGHPASS FILTER: 21 Hz 24 dB/oct LR

TRANSDUCERS: One K-472 18" woofer w/4" voice coil

 

THT: 

Not sure of specs, but I think it's good down to 22Hz, and the efficiency is something like 103db each, which would make 3 of them 109db efficient. Power handling would be something like 500W each, which would be 1500 for 3 of them. Weight of 3 of them would be 450-500lbs. Max output continuous should be something like 139db between 22 and 250Hz. Drivers 3 15" Dayton HFs.

Edited September 14, 2014 by mustang guy

[Chris A]

I'd recheck your numbers for the THT - I doubt that the sensitivity of a single box is 103 dB across the pass band, and I doubt that its -3dB point is half space is 22 Hz - more like 40 Hz or higher.

 

THT in half space:

 

Edited September 14, 2014 by Chris A

[mustang guy]

Chris,

 

I read through that thread, and I don't know what to tell you. I have a pair of THT's sitting beside my center LS, and there is no freaking way on this Earth that those measurements are right. 

 

I don't understand how he screwed them up, but he did. As far as horn length goes, 9' isn't close. I have the plans and have measured it, and it is just under 13'.

 

When I'm down at the shop, I will do a pink noise directly into the crown amp and grab an FFT for you all. I don't know about the efficiency, but I can do that too. I'll measure pink at 1 meter w/2.83V. That should clear this up... 

[mustang guy]

Here is BMF's response to that graph:

 

[jason str]

That chart is not correct at all, whoever posted that either did not know what they were doing or the build is off somewhere.

 

Driver way out of spec.

Open driver chamber.

Huge air leaks.

All the above.

 

Have a read here for measurements ot visit the Bill Fitzmaurice forum for better information.

 

By the way, 3 15s would far surpass 1 18" driver.

[mustang guy]

That chart is not correct at all, whoever posted that either did not know what they were doing or the build is off somewhere.

 

Driver way out of spec.

Open driver chamber.

Huge air leaks.

All the above.

 

Have a read here for measurements ot visit the Bill Fitzmaurice forum for better information.

 

By the way, 3 15s would far surpass 1 18" driver.

It may seem counter-intuitive, but three 15's may or may not outperform a single 18. There is a bit more to it than that, the least of which is the total volume. The 1802 has a greater total volume. There is also the matter of horn length and the T/S specs of the drivers used. 

 

As I understand it, the 1802 uses an 18" driver, and a passive plus horn loads everything. To say 3 15's beat an 18 and a passive that are horn loaded is guessing.

[jason str]

The KPT1802 has no passive radiator, its a ported design.

 

The max SPL of the THT is 127 dB, add 2 more THT's and it would far surpass the 130 max SPL of the KPT1802, no guessing involved

[Chris A]

In God We Trust - everyone else bring data....

 

You have half-space test data, i.e., out of doors on the ground....?

 

Post it - then I'll believe it. Otherwise...based on the numbers I've got, the KPT-1802 should outperform three THTs--below 40 Hz--hands down.

Edited September 14, 2014 by Chris A

[jason str]

[Turbox]

There is no passive, its vented. Strange looking thing for sure. single 18 with a vent where the other passive or woofer would be. see the pics part way down the page.

 

https://community.klipsch.com/index.php?/topic/147802-klipsch-kpt-1802-hls-horn-subwoofer/page-4?hl=1802

[Turbox]

I've never heard the THT. But I can tell you, I was having my own little listening party yesterday. There were some points in the music where the music stops, and the bass drops off. there were a couple points in the music where I couldn't hear a darn thing...but I could feel the bass, couldn't hear it. but could feel it in the floors and such. it was kinda cool. Had to be down near 20Hz for sure.

[jason str]

Yes, just because your sub is rated down to 25 Hz +/-3dB or whatever room gain would bring that number far lower, of course your results will vary with room dimensions.

[mustang guy]

There is no passive, its vented. Strange looking thing for sure. single 18 with a vent where the other passive or woofer would be. see the pics part way down the page.

 

https://community.klipsch.com/index.php?/topic/147802-klipsch-kpt-1802-hls-horn-subwoofer/page-4?hl=1802

Sorry, I meant vented. My memory isn't what it used to be. Vented provides tuning capability, which means that on top of the T/S specs of the 18" drivers Klipsch uses, the volume of the cabinet, and the horn path, the actual beginning frequency of the enclosure before the horn path is reduced/tuned to a lower frequency. This evens the playing field, IMO. 

 

I am not going to drag my THT's outside to perform the test. My building is 130,000 cu ft, and I doubt there will be little gain at 2.83 volts. In fact, the ambient noise of outdoors is much more likely to taint the results than a very slight reflection from 60' away.

 

I will give an unbiased measurement based on these parameters. To confirm the results, I will test my second THT in the same position. Then I will test both subs together to see if there is indeed a 3db gain. From there, we should be able to hypothesize it would be 2/3 of what three THT's stacked will accomplish.

[whatever55]

Here is BMF's response to that graph:

 

Could have been someones early build....  learning curve and all.....  buyer beware

Edited September 15, 2014 by whatever55

[mustang guy]

In God We Trust - everyone else bring data....

 

You have half-space test data, i.e., out of doors on the ground....?

 

Post it - then I'll believe it. Otherwise...based on the numbers I've got, the KPT-1802 should outperform three THTs--below 40 Hz--hands down.

This thread is getting more interesting by the moment. Jason, where did your graph come from? That would help with credibility. Unless Bill Fitzmaurice was lying or mistaken, the graph Chris displayed was from a bad THT. 

 

There are certainly many reasons a person would go to a lot of trouble measuring a sub. One of them might be under-performing it's expectations. It is possible, then, that the person who was testing the sub knew there was something wrong, and instead of pointing his bony finger of blame at the builder, he threw bill Fitzmaurice under the bus.

Edited September 15, 2014 by mustang guy

[mustang guy]

 

Here is BMF's response to that graph:

 

Could have been someones early build....  learning curve and all.....  buyer beware

 

I have built 2, and I can tell you that no matter how good you get, you cannot build one of these in 4 hours. Jason and many others here will back me up on that.

[mustang guy]

Hey Turbox, FYI, I think the KPT-1802 is the awesomest sub out there. I am definitely not trying to poo-poo them. I was just bored, and had this idea.

[Chris A]

 

Check the vertical scale of this graph in relation to the one I posted - the curves are very close to the same. 

 

My comment on the relative performance below 40 Hz for the THT and the KPT-1802 are basically unchanged.

[jason str]

The posted information is here on the forum, i posted the link earlier in this thread but here it is again.

 

DIY sub for Klipschorn based HT (and music) - Tuba HT - build done (except for finish)!

 

Bill Fitzmaurice forum has similar posts on the subject, all are very close except for the bullshit chart that appeared earlier in this thread, this misinformation was also posted previously in other threads by Dr Who if i recall.

 

Bill clearly lists frequency charts in the SPL chart page on his forum, looks very similar to what i posted here today.

 

BFM THT SPL chart.

[jason str]

 

 

Check the vertical scale of this graph in relation to the one I posted - the curves are very close to the same. 

 

My comment on the relative performance below 40 Hz for the THT and the KPT-1802 are basically unchanged.

 

 

 

I disagree but the people on the forum can come to their own conclusion on the subject with the information provided here or look into it with more detail on the BFM forum.