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post #1 of 15 Old 08-22-2019, 09:57 AM - Thread Starter
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Odd Room Shape Acoustics: Dual or Single?

Hi all,


Long time lurker, first time poster looking for advice on how much I should take room acoustics into account when deciding between a single HSU VTF-3 HP or dual VTF-2 MK5's (will likely start off with one).


I know the room is a major factor, but am curious as to whether my room is a "good" or "bad" factor, meaning would getting 2 to start with save me time and hassle because my room is so "wonky", or do all the slants, nooks/cranny's, etc. in my room mitigate standing waves and lend itself better to a single to where I likely wouldn't need duals to have reasonably solid bass coverage.



Room Details
  • Combination man room, office and home theater - carpeted with drywall
  • Location: bonus room over 2-car garage (single-family home)
  • Dimensions: roughly 22 ft (the wall w/TV on it) x 14.5ft (the wall w/window) x 8 ft ceiling with 5 ft knee walls. Please refer to the attached pictures showing 2D and 3D versions of:
    • Current setup
    • Dual VTF-2 preferred option
    • Single VTF-3 options 1, 2, and 3
  • Seems to calculate to roughly 2,500-2,600 ft3

Current Equipment
  • Onkyo TX-NR686
  • L&R: ,DefTech BP10
  • Center: DefTech CLR1000
  • Rear surrounds: DefTech ProMonitor1000
Situation
  • I have probably read every thread on the single vs. dual theory, and I like the idea of duals to mitigate any peaks/nulls, but would like to start with a single sub to make sure I don't fall down the rabbit hole too quickly and buy more than I truly need.
  • The shape of my room is so odd, I am wondering if it would actually less, or more, likely to produce standing waves, again, meaning should I go straight for duals because my room either doesn't have a good spot for a single, or because the room acoustics essentially dictate the need for duals
Question
  • Stipulating that I will work on experimenting and tweaking placement, does my room "lean" toward needing duals, or is it reasonable to assume that the dimensions, slants, etc. increase the potential for one sub to work in one the locations indicated?
  • If duals are highly likely:
    • I plan on starting with the VTF-2 as I like them up front and would be more than adequate in my room
  • If a single works:
    • I will go with a VTF-3 as I think two VTF-3s would be overkill (for my wife, since she tells me to turn down some movies with just my BP10's right now). Plus, they won't fit flanking my TV up front. I supposed I *could* add another VTF-3 later, but would really prefer to make the right call now and then just enjoy my system.
Thanks so much, in advance. I know these questions get asked a lot (I've read all the threads) but hopefully this question has not been asked in quite this way before. I appreciate the hive knowledge here and look forward to the ensuing discussion.

Thanks!
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post #2 of 15 Old 08-22-2019, 01:58 PM
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2 VTF2.5s in that size room would be plenty for most people. So if you don't plan on or want reference level bass under 20hz you should be fine. It does somewhat limit any future upgrades though.

IMO you should get the most powerful sub you can now and then add another later. Always better to have it and not need it than to need it and not have it.
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post #3 of 15 Old 08-22-2019, 02:14 PM - Thread Starter
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Quote:
Originally Posted by Kini62 View Post
2 VTF2.5s in that size room would be plenty for most people. So if you don't plan on or want reference level bass under 20hz you should be fine. It does somewhat limit any future upgrades though.

IMO you should get the most powerful sub you can now and then add another later. Always better to have it and not need it than to need it and not have it.

Thanks. So what is your though on two VTF-2's vs the one VTF-3? Obviously the VTF-3 is the "better sub I can afford" and wouldn't anticipate getting two of those, but the dual VTF-2's should better mitigate any peaks/nulls.
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post #4 of 15 Old 08-22-2019, 03:35 PM
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The main advantage with 2 subs is that each sub can compensate for the other sub's peaks & nulls, averaging the response to get smoother bass across the seating area. Can't do that with a single sub (it can't fill in its own peaks & nulls). Worth starting off with 2 subs.

The other thing I would do is spread the 2 surround speakers to the back corners of the room. From your diagram, it looks like the surrounds are a foot away from listeners on either end of the couch. Really distracting.

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post #5 of 15 Old 08-22-2019, 06:59 PM
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Magic happened for me after 3 subs. I was one of those people also who would rather have 2 mediocre subs now vs. 1 great one now and one great one later. 6 subs later I am content with 2 18" rss460ho and a small Dayton sub1200. I think I may still get a better amp for the 18" and upgrade the 12" to a 15". I can't fit big ported... I get it. I guess what I am trying to say is the advice everyone told me to get the biggest and best you can then get another down the road would have saved me money in the end.
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post #6 of 15 Old 08-22-2019, 07:29 PM
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Quote:
Originally Posted by DS3 View Post
Thanks. So what is your though on two VTF-2's vs the one VTF-3? Obviously the VTF-3 is the "better sub I can afford" and wouldn't anticipate getting two of those, but the dual VTF-2's should better mitigate any peaks/nulls.
Two VTF3s over the course of a couple years is not really that much more money but they're a lot more sub.

You won't know how your room responds with just one sub until you try it. You'll probably be happy with the pair of VTF2.5s based on your comments. So go that route.

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post #7 of 15 Old 08-23-2019, 05:56 AM - Thread Starter
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Originally Posted by sdurani View Post
it looks like the surrounds are a foot away from listeners on either end of the couch. Really distracting.

Actually, they're closer to 5.5 feet from the center of the sofa, which is MLP. The only other listener is my son, and he just thinks it's cool to have sounds behind him, lol. I wanted to mount them to the wall, but the one being MLP-left was beyond 50 feet of cable, and if I move them much further away, the recliners get in the way when reclined. I may move them around later, but for now, they work pretty well where they are.
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post #8 of 15 Old 08-23-2019, 06:14 AM - Thread Starter
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Originally Posted by LGERIC View Post
Magic happened for me after 3 subs. I was one of those people also who would rather have 2 mediocre subs now vs. 1 great one now and one great one later. 6 subs later I am content with 2 18" rss460ho and a small Dayton sub1200. I think I may still get a better amp for the 18" and upgrade the 12" to a 15". I can't fit big ported... I get it. I guess what I am trying to say is the advice everyone told me to get the biggest and best you can then get another down the road would have saved me money in the end.

And this is exactly what I'm afraid of, lol. I really would like to try to get this right the first time. I guess I was hoping that the shape of my room would provide some extra "insurance" against standing waves, since there were so many angled walls, thereby permitting a single excellent sub (VTF-3) that wouldn't need to be placed in an awkward location just to minimize peaks/nulls. I have tried some of the online room mode calculators, but I don't understand what they're telling me...

I guess this is coming from having to pay to return the HSU's vs SVS having it built into their pricing, but HSU's seem to be the better sub for the money - you just can't experiment as easily. Like I said before, I really want to achieve the most even performance while easily getting down to 18-20Hz. I don't need reference levels, I just don't want any nasty booming or dead spots.
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post #9 of 15 Old 08-27-2019, 06:06 AM - Thread Starter
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Quote:
Originally Posted by DS3 View Post
Hi all,


Long time lurker, first time poster looking for advice on how much I should take room acoustics into account when deciding between a single HSU VTF-3 HP or dual VTF-2 MK5's (will likely start off with one).


I know the room is a major factor, but am curious as to whether my room is a "good" or "bad" factor, meaning would getting 2 to start with save me time and hassle because my room is so "wonky", or do all the slants, nooks/cranny's, etc. in my room mitigate standing waves and lend itself better to a single to where I likely wouldn't need duals to have reasonably solid bass coverage.



Room Details
  • Combination man room, office and home theater - carpeted with drywall
  • Location: bonus room over 2-car garage (single-family home)
  • Dimensions: roughly 22 ft (the wall w/TV on it) x 14.5ft (the wall w/window) x 8 ft ceiling with 5 ft knee walls. Please refer to the attached pictures showing 2D and 3D versions of:
    • Current setup
    • Dual VTF-2 preferred option
    • Single VTF-3 options 1, 2, and 3
  • Seems to calculate to roughly 2,500-2,600 ft3

Current Equipment
  • Onkyo TX-NR686
  • L&R: ,DefTech BP10
  • Center: DefTech CLR1000
  • Rear surrounds: DefTech ProMonitor1000
Situation
  • I have probably read every thread on the single vs. dual theory, and I like the idea of duals to mitigate any peaks/nulls, but would like to start with a single sub to make sure I don't fall down the rabbit hole too quickly and buy more than I truly need.
  • The shape of my room is so odd, I am wondering if it would actually less, or more, likely to produce standing waves, again, meaning should I go straight for duals because my room either doesn't have a good spot for a single, or because the room acoustics essentially dictate the need for duals
Question
  • Stipulating that I will work on experimenting and tweaking placement, does my room "lean" toward needing duals, or is it reasonable to assume that the dimensions, slants, etc. increase the potential for one sub to work in one the locations indicated?
  • If duals are highly likely:
    • I plan on starting with the VTF-2 as I like them up front and would be more than adequate in my room
  • If a single works:
    • I will go with a VTF-3 as I think two VTF-3s would be overkill (for my wife, since she tells me to turn down some movies with just my BP10's right now). Plus, they won't fit flanking my TV up front. I supposed I *could* add another VTF-3 later, but would really prefer to make the right call now and then just enjoy my system.
Thanks so much, in advance. I know these questions get asked a lot (I've read all the threads) but hopefully this question has not been asked in quite this way before. I appreciate the hive knowledge here and look forward to the ensuing discussion.

Thanks!
A quick bump to see if there are any other opinions as to how much the shape of my room would benefit a single subwoofer (I am curious whether the knee walls, slanted ceilings, and other features would help prevent standing waves since there is less perfectly parallel surfaces), and whether it would be enough to drastically reduce the need for two.


TIA!
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post #10 of 15 Old 08-27-2019, 09:11 AM
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Hi. Fellow odd shaped room guy here. In fact, mine is freakishly odd with multiple corners and angles. I was able to get things pretty even with two subs but only after measurement and some thoughtful problem solving.

Let me start by explaining what everyone is saying here. Almost all rooms in houses and apartments are lousy for bass. If you take a measurement at your listening position almost all locations will graph like a roller coaster. This means some frequencies will have peaks (where bass is being delivered well … sometimes too well) and nulls (where little to no bass is being delivered).



Before I "splurged" on a $70 microphone I located my sub doing the "sub crawl." The green line above was the spot in my room where bass sounded the "loudest." In actuality, I was only hearing limited parts of the bass spectrum. It was loud bass, but only at like 23Hz and 53Hz. But, the spot in my room that made the red line, which by itself didn't sound that great, ended up complimenting the first location very well. Together they make very nice bass across the entire spectrum. So, there's no magic to two subs - unless you locate them in places that allow them to make up for the other location's shortcomings.

We spend many thousands of dollars on this hobby trying to make something that sounds good and provides enjoyment. Add up the cost of a receiver, main speakers, surround speakers, subwoofers, etc. and it's got to be at least several thousand. What if there was a magic thing that could take what you have and make it sound MUCH, MUCH better? And what if that thing only costed $70?

https://www.minidsp.com/products/aco...urement/umik-1

When you ask "how many subs do I need" or "where should I put them?" you, me, and all the helpful folks here are just guessing. They may be educated guesses, but none of us know. Especially with odd shaped rooms! But for $70 you can know EXACTLY what you have, what locations are best, and what secondary locations fill in whatever gaps those primary locations might have.

SPEAKERS: 3 x DIYSG 1099's LCR; DIYSG HTM 6's and 8's surround; 4 x RSL C34E's atmos.
SUBS: 4 x UM18-22 Mini Marty's (and always building, currently working on Devastators).
SIGNAL CHAIN: Denon X4400; Minidsp 2x4 HD; 2 x Jensen Iso Sub 2RX; 2 x NX6000d.
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post #11 of 15 Old 08-27-2019, 09:32 AM
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seems like the smaller VTF-2 MK5 would be easier to place in a tight room like that. Especially when you go with duals or more

Speakers: KEF Q100, Q300, Q750, Q650C / Fluance Signature Series Bookshelf, SX6, XL5F/ Mirage M-190 / DCM TP160S-CH Subwoofers: Outlaw Ultra X12 (x2) / BIC H100-II
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post #12 of 15 Old 08-27-2019, 12:51 PM - Thread Starter
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Quote:
Originally Posted by lawdogx View Post
I was able to get things pretty even with two subs but only after measurement and some thoughtful problem solving.

H. Thanks for responding. So, it sounds like I should plan on two subs for my multi-faceted room as well? Is your room of similar volume?


Quote:
Originally Posted by lawdogx View Post
there's no magic to two subs - unless you locate them in places that allow them to make up for the other location's shortcomings.

We spend many thousands of dollars on this hobby trying to make something that sounds good and provides enjoyment. Add up the cost of a receiver, main speakers, surround speakers, subwoofers, etc. and it's got to be at least several thousand. What if there was a magic thing that could take what you have and make it sound MUCH, MUCH better? And what if that thing only costed $70?

Ok. I think you sold me. I'll plan on getting the minidsp to assist sub placement. I have a tendency to overthink things and it seems like I'm not alone...here anyway, lol. Anyway, the minidsp looks like it will take the guesswork out of placement and provide a measure of comfort that I'm not just hearing loud bass in a small frequency window like you had.
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post #13 of 15 Old 08-27-2019, 12:57 PM - Thread Starter
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Originally Posted by macgallant View Post
seems like the smaller VTF-2 MK5 would be easier to place in a tight room like that. Especially when you go with duals or more

Another vote for duals. It seems to be the "easy answer" to mitigate standing waves. I just want to reasonably confident in my initial purchase to know whether a single VTF-3 + my room would yield good coverage of the sub 100Hz range (will probably xover at 80Hz anyway), or whether dual VTF-2's would be better, since I really don't have the budget for 2 VTF-3's. Heck, I'll probably have to start with a single VTF-2 if I go duals anyway.
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post #14 of 15 Old 08-27-2019, 02:45 PM
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Quote:
Originally Posted by DS3 View Post
H. Thanks for responding. So, it sounds like I should plan on two subs for my multi-faceted room as well? Is your room of similar volume?

Ok. I think you sold me. I'll plan on getting the minidsp to assist sub placement. I have a tendency to overthink things and it seems like I'm not alone...here anyway, lol. Anyway, the minidsp looks like it will take the guesswork out of placement and provide a measure of comfort that I'm not just hearing loud bass in a small frequency window like you had.
My ridiculous freak room is much worse than yours. I was still able to find two spots that summed nicely. I first used two VTF-15's and they sounded great. I've since moved to four huge custom 18" subs, but my goals are different than yours. I want Godzilla's steps to knock pictures off the walls in the next room and sound like my house is exploding. But I digress ... The process is an over-thinker's paradise.

First I identified every location in the room that could fit a sub, whether it was pretty and convenient or not. I have 12 potential spots. I then grabbed some furniture sliders and pushed the sub into each of those locations.



I was then able to compare my potential spots. The results of all of them will look like spaghetti.



You then find the best location, and then whatever second location fills in whatever nulls the first has. It's just problem solving 101.

You start by buying this mic:

https://www.minidsp.com/products/aco...urement/umik-1

Downloading this free software:

https://www.roomeqwizard.com

and following a set up guide.I like this one:

https://www.minidsp.com/support/comm...by-austinjerry

There's also a great thread here on AVS:

https://www.avsforum.com/forum/91-au...et-graphs.html

Welcome to the rabbit hole!

SPEAKERS: 3 x DIYSG 1099's LCR; DIYSG HTM 6's and 8's surround; 4 x RSL C34E's atmos.
SUBS: 4 x UM18-22 Mini Marty's (and always building, currently working on Devastators).
SIGNAL CHAIN: Denon X4400; Minidsp 2x4 HD; 2 x Jensen Iso Sub 2RX; 2 x NX6000d.
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post #15 of 15 Old 09-18-2019, 01:16 PM - Thread Starter
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Hi all, I wanted to post a follow up.


My VTF-3 Mk5 arrived today!



I've got it in the front left corner pointed at the MLP and I am getting ready to start setting it up, but I had a couple of questions as I'm planning on using the Onkyo AccuEQ on my TX-NR686 (no standalone SPL meter or UMIK...yet) and setting the crossover at 80Hz in the AVR:


  • For those of you with HSU's, I read somewhere that in a room like mine, that can fully closed off, I am better off started with a lower Q, like.5 or even .3 to prevent my AVR from dialing it back too far. Is there any logic to this, or should I stick with the instructions it came with?
  • Second, for those of you with Onkyo's, how much do you trust the distance and level settings AccuEQ recommends? I ran mine the other day again, just for fun and the distances were quite a bit off from the actual distances I measured myself. Is that because it's wrong, or because it is setting the distances needed to coordinate the simultaneous arrival of sound from all speakers at the MLP?
Thanks!!
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