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HT 2 12" subs vs 1 15" sub


Ryan from WA

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I currently have 2 12" klipsch r-12sw subs for my HT as well as klipschorns up front and Im wondering if I would be better off with a 15", looking at the 115sw specifically. Would I improve the sound? Do the 12s not match with the klipschorns? Im thinking about trying to facilitate a 2 for 1 trade - Two 15" subs are not in the budget currently. To me the current setup sounds okay but I am easily impressed. I also dont have my permanent surrounds/center so I dont have a complete setup to judge yet.  Thanks for any input!

 

Ryan

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I would normally say 2 subs are better than 1 but the 115 is a significant step up from the r-12sw. I would say the quality of the bass and the output of a single 115, should easily out pace the dual 12's, depending on whether you can put the 15 in the optimized spot in your room. 

 

Buying subwoofers is fun;)

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If you like the sound you have, it is already perfect.  Another's opinion is irrelevant. 

 

Two 12s have 1.3x the piston area of one 15.  So, I'd keep the 12s and add an R-115sw or even add more R-12s.  More cones/cone area means less excursion and therefore less distortion for a given sound pressure level.  More subs around the room means more even bass response where ever you sit in that room.  A sub in the front center and two near the center of the side walls would be a grand beginning.  Placing your 2 near the center of the front and rear walls or side walls is a good place for what you have.  Be sure they are against the wall.  i.e. More Cowbell!

 

The R-115 goes deeper and gets louder, but really there are nearly no instruments that will be played that go below the 30.9 Hz of an open B string on an 5-string electric bass or organ pedal.  Even that is rare.  The theme to "Titanic" has some 21.8 Hz F0 synthesizer notes, a true exception.  I'm unsure how deep special effects in movies might go, but I doubt they are below 25 Hz, a common limit for theater subwoofers. 

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Special effects go down as low as 7hz (depth charges in u571) in HT and is more common than the past.  I consider 15hz to be the practical limit in homes but its easy to get extension to 10 in a lot of rooms.

 

JAs ideas are great listen to his suggestions above.  add to your 12s if anything.  2 15s is better than 2 12s but i wouldnt go to 1 sub from 2 in most situations. So yes a 115 is a much better sub but until u get 2 (used?) dont replace the existing ones.

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Thanks for the great responses! I picked up a pair of heresy 1s earlier today and swapped them in to my surrounds (rear L+R - replacing a couple small klipsch quintet speakers) and watched a couple movies... Even with having quintets as the center and surrounds (barely heard with the klipschorns up front) the addition of the 1 pair of heresies made such an impact to the sound quality that I am very happy with my current subwoofer situation. It showed me where improvements are needed and where they are not. I ordered a new pair of heresy 3s a week ago that Im waiting to come in, and my plan is to use them both as my center channel. Ill keep an eye out for a final pair and a proper amp to power these 6 speakers and Im confident I wont feel like Im missing anything... For a while. Then on to my first projector endeavor.

 

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18 hours ago, derrickdj1 said:

You don't really need two center speakers.  Go for a 6.X system.

I am trying to keep my center speaker under 24-30 inches tall so the projector screen I eventually get can get down that low. That rules out a cornwall or a belle or la scala that might be a better fit with the klipschorns. Would a single heresy speaker provide a good sound as a center in this setup?

Edited by Ryan from WA
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My main experience is with car audio. I was an installer for some years. 12s are definitely harder hitting than a single 15. The smaller sub will react quicker to fast bass notes. With 12s you'll be able to differentiate between quick bass notes, while 15s will rumble the bass notes. SPL wise, which many customers seek, I think 12s are harder hitting. I have heard systems utilizing 48 4" woofers (extremely quick bass notes), multiple tens, 12s, 15s, 18s, and larger, but 12s seemingly are the most well rounded size. The larger the woofer the more lazy sounding the bass notes. Less distinction is heard.

 

I would love to hear what others think. But I tend to believe you should go for overall surface area. The area of 2 12" woofers is greater than a single 15" woofer. There should be no question as to which is going to produce more sound with quicker bass notes.

Edited by Shimei
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The 12's don't dig as deep as the 15's.  Two 15's is where it's at.  If you don't care about the 18-20 hz extension for home theater, I'd be trying to get into the pro line like with a 684.  One R-115SW wouldn't be that complimentary for music with K-horns in my opinion.  

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9 hours ago, Shimei said:

My main experience is with car audio. I was an installer for some years. 12s are definitely harder hitting than a single 15. The smaller sub will react quicker to fast bass notes. With 12s you'll be able to differentiate between quick bass notes, while 15s will rumble the bass notes. SPL wise, which many customers seek, I think 12s are harder hitting. I have heard systems utilizing 48 4" woofers (extremely quick bass notes), multiple tens, 12s, 15s, 18s, and larger, but 12s seemingly are the most well rounded size. The larger the woofer the more lazy sounding the bass notes. Less distinction is heard.

 

I would love to hear what others think. 

 

Just not true.  No such thing as fast bass and slow bass.  There is only midrange extension, proper enclosure design, and driver transient response, the latter of which is kind of negated by the room.  Speed in a subwoofer driver equates to SPL, not definition.  Definition is controlled more by voice coil inductance (Le) than driver diameter, due to nice midbass and midrange extension, as well as blending nicely with your mains.  

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1 hour ago, MetropolisLakeOutfitters said:

 

Just not true.  No such thing as fast bass and slow bass.  There is only midrange extension, proper enclosure design, and driver transient response, the latter of which is kind of negated by the room.  Speed in a subwoofer driver equates to SPL, not definition.  Definition is controlled more by voice coil inductance (Le) than driver diameter, due to nice midbass and midrange extension, as well as blending nicely with your mains.  

 

Thanks, but by quick bass notes I am referring to a track with a series of fast following percussions. Say there are ten hard hitting bass notes one after another that occur rapidly. I have never heard a 15 or 18 + subwoofer reproduce the series as distinctly as 10s or 12s.

 

 

 

Edited by Shimei
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  • 3 years later...

Let's discuss "fast bass" for a moment.

 

There is no such thing. By definition, all bass is "slow", otherwise it would be treble. But I don't think that's what people are talking about when they say "fast bass".

 

Where bass differs is in transient response. Since this is a Klipsch Forum, I'll provide some examples using a Klipsch K33E driver. But this same phenomenon applies to any driver, with the enclosure size and tuning adjusted as appropriate.

 

Included below is a screen capture of WinISD applied to the K33E driver. The heavy green line represents WinISD's recommended vented QB3 alignment, tuned to about 34 Hz. Each of the other green lines represents the response with the same driver, in progressively larger enclosures tuned to progressively lower frequencies. The blue line represents the K33E in a sealed enclosure, Linkwitz-Transformed to Q=0.7071 and 34Hz tuning, to match the cutoff frequency of the vented QB3. Note that all of these responses can legitimately be characterized as +0/-3 dB in the passband.

 

To be continued ...

WinISD_comparison.png

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Here is the tone burst response of the 33 Hz tuning. Note that it continues to oscillate for even longer than the QB3. So the price of the lower cutoff frequency is more oscillation after the end of the tone burst.

 

To be continued ...
 

VentedBox33Hz.png

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  • 1 month later...
On 11/8/2020 at 2:07 PM, Edgar said:

Finally, here is the tone burst response of the closed box. Best of the bunch. And that, I believe, is what people mean by "fast bass".

ClosedBox34Hz.png

Right, by “fast” they mean quick response, as shown in your graphs. Thus the rock song with machine gun double kick drums wants fast more than deep. The church organ pipe that comes on at 20 Hz and then sits there for a half note or longer doesn’t need fast. Fast is always good but not necessarily required. I’d love to see your graphs for a fast kick drum and a ten foot wooden or metal organ pipe. I’ll bet the pipe is “slow”, think about getting all that air moving.

Edited by Pondoro
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