Subwoofer replacement question for 7.2.4 system - 1 large or 2 mismatched?

[flint350]

Recently I bought a new Onkyo RZ70 to replace an aging Denon in a 7.2.4 system that is used for movies and music. The speakers are all Polk floorstanders and a 10" Polk sub and 10" Episode sub (I have 2 but use 1.) I came across a great value (1/2 price at $700) Black Friday deal on a new Klipsch RP-1400sw 14" subwoofer and bought it before time expired.

In the current setup, I don't mind pairing the Polk 10" sub w/ the Episode 10." However, now I am trying to decide if I should use the new 14" with the Polk 10" or just change to a 1 sub setup (7.1.4) since the 14" is much larger and more powerful. I have Dirac Live and double bass add-on to run the EQ. So: is it just a matter of try both and see (hear) the difference, or is there a reason why I should just retire the smaller subs altogether due to size or mismatching, etc.? The room is fairly large with 19' front wall, 13' to rear seat w/ open back to kitchen and 10' ceilings. All speakers are set in very good positions, no oddball walls or spaces. Thanks for any constructive input.

 

[AnalogSteph]

When it comes to evening out the bass response across a room, the more subs the merrier. That being said, architecture is going to be a factor - walls made from a whole lotta nothing are going to leak more than a massive concrete affair, shifting things more towards output level than room modes.

If I'm not mistaken, twin 10" subs should have a surface area roughly equivalent to a 14", so you might consider combining your two existing subs to form your "second sub".

 

[flint350]

Thanks

 

[Willem]

The more the merrier. I use three subs and all are different in brand and size. Earl Geddes in fact recommends at least three, with one of them much larger than the others. Mine are equalized with MSO.

 

[flint350]

The new 14" arrives tomorrow (Wed) and I have decided to wire in series the two identical 10" Episodes I have. That should make a decent partnership. During the recent sale at Dirac Live, I bought the double bass add-on for $240, so that should help in calibrating my frankensub combo.

 

[Willem]

The best way to use all this is to use all three, and equalize them independently. Earl Geddes recommends using the biggest sub in the front corner for maximum extension and power, and distribute the other two in uncorrelated positions, and equalized individually for smoothest combined response in the range 30 (?)-80 Hz. Using MSO probably gives you the best result across the largest listening area. That is what I did, and the result is very even, wherever I sit. I am pondering even getting a fourth, and lifting it well above the floor, for a smoother response in the vertical plane as well.

 

[flint350]

I actually will have 4 when the new 14" gets here. The other 3 are 10" (2 episode & 1 Polk). My AVR supports 2 subs out, which is why I was thinking of combining the 2 identical 10" subs into 1 and then run Dirac Live. Thanks for the input.

 

[Willem]

For best results, you could consider using Multi Sub Optimizer with a mini DSP 2x4HD, equalizing all four subs individually. You can always add Dirac on top of that. However, MSO is hard work.

 

[574stereo]

You absolutely must not mix and match subwoofers. They all have vastly different phase responses. While you'll be putting more energy out into the room, if they're not playing in phase with each other you're going to just cause all sorts of lobing issues and uneven responses across the room.


Subwoofer phase responses can deviate from each other by as much as 80 msec in extreme cases. Even 5-10 msec is going to be enough to do some very, very weird stuff to your in-room response.

 

[Willem]

Floyd Toole would disagree, but does advise against mixing sealed and ported subs, and that is all. MSO will deal with the rest.

 

[flint350]

Everything is now in place, as the RP-1400 arrived (mostly) undamaged - despite UPS' best efforts to attack the box. I will make my first run at Dirac Live +Bass and see (hear) the results. My other consideration is simply selling/donating the odd subs and buying 1 additional series-matching sub, like the 12". I appreciate all of the comments and advice.

 

[FunkIT]

A friendly nudge to spread your L & R mains further apart

 

[akamatsu]

I use one subwoofer, and I can't even locate it in the room by listening. But my room is much smaller than yours.

 

[AdamG]

Everything is now in place, as the RP-1400 arrived (mostly) undamaged - despite UPS' best efforts to attack the box. I will make my first run at Dirac Live +Bass and see (hear) the results. My other consideration is simply selling/donating the odd subs and buying 1 additional series-matching sub, like the 12". I appreciate all of the comments and advice.

Beautiful room. Looks comfy and cozy. Best luck taming all those subs. It can get messy and I have no additional advice to what you have already elicited. Except, remember to have fun along the way. Get a Microphone and take before and after measurements so you can visualize the improvements. Watching all your movies again with better Bass is going to put a permanent smile on your face through Christmas at least.

 

[flint350]

First effort after using Dirac Live/Bass Control was pretty satisfactory. Sound from the subs seems controlled and part of the 3d bubble when using Atmos tracks. In stereo for music the speakers disappear (2.2) and soundstage is very good. My only qualm is that I realized during the setup for Dirac, I set the subs at a standard crossover of 80, and I have since read that they should be set to max crossover for calibration. I'm going to re-do it and save to a different preset so I can compare the results. But, I must say my first go at Dirac/Bass sounds pretty good to these old ears, tinnitus notwithstanding. I can thank my aviation career for that downfall. And sincere thanks again for all the helpful input and suggestions!