[DaveyMac]

I have a feeling that my livingspace is god awful for two Subs. Pictures attached. Please note the baby playcrib just happens to be out there, usually it’s just couch and HT in the room.

Here are the spots, I'm thinkingof

1. Wherethe one is already located(left of couch and window) – Main listening position is right next to it.


2. The other corner where a largebookshelf is (right of couch and window). I can get rid of book case there orput it in front of bookcase a foot off of wall.


3. To the right of TV (as you arelooking at TV) – there is enough room there in that corner pocket.


4. The couch is an ‘L’ shape –could potentially place on the left side of couch
where the shorter part of ‘L’ ispointed towards dining room


5. On the back wall next to wherethere is an aquarium (lizards are in it).


I'm pretty stupid on this stuffso I guess I'm leaning towards 2 and 3. Any better ideas. Would you point portsat Wall or middle of room?

 

[nalthien]

The only way to know where to place your subwoofers optimally is by doing a subwoofer crawl and / or measuring with a tool like Room EQ Wizard. Unless you're asking for purely aesthetic purposes, there's no advice anyone can give on placement just by pictures of the room.

 

[Red99]

Yeap, google subwoofer crawl, or search on here. Its very important if you want the best bass sound.

 

[derrickdj1]

The crawl will not be much good with limited options. A second small sub could go behind the R main speaker in the corner. I think this will give you a better room response. We all have to work with what space we have.

 

[DaveyMac]

The crawl will not be much good with limited options. A second small sub could go behind the R main speaker in the corner. I think this will give you a better room response. We all have to work with what space we have.

So probably try the corner where bookshelf is and to right of TV.? That would be opposite corners of room.

If I try the sub crawl again, I know to put sub at MLP. But I'm trying to implement two subs. Do I put one sub at MLP - and then find best spot, put second sub there - then crawl again for position the MLP sub will ultimately go?

 

[nalthien]

I think it's Alan P who has developed a good methodology for doing the dual-subwoofer crawl. However, in basic terms, you basically crawl one, and then, while that one is placed, crawl for the other to see where you get the best results for both being on.

 

[DaveyMac]

I think it's Alan P who has developed a good methodology for doing the dual-subwoofer crawl. However, in basic terms, you basically crawl one, and then, while that one is placed, crawl for the other to see where you get the best results for both being on.

Got it! If I end with them in corners or against walls - do you typically want them facing wall or towards MLP?

 

[nalthien]

Got it! If I end with them in corners or against walls - do you typically want them facing wall or towards MLP?

As long as they are several inches away from the walls, it won't matter. Frequencies under about 100hz can't really be localized so it'll be fine either way.

 

[derrickdj1]

Using the corner by the TV will most likely give you great output and a smaller sub can work there. From your pic's, you are right about the limited options. The sub crawl is less effective as the number of subs goes up. Level match the subs and call it a day and enjoy. You can always tinker more if you get Omnimic or REW.

The benefit of the second sub is for a better room response and a little extra spl.

 

[DaveyMac]

Using the corner by the TV will most likely give you great output and a smaller sub can work there. From your pic's, you are right about the limited options. The sub crawl is less effective as the number of subs goes up. Level match the subs and call it a day and enjoy. You can always tinker more if you get Omnimic or REW.

The benefit of the second sub is for a better room response and a little extra spl.

Thanks Derrick, I don't think I level match if they are identical? They are both HSU VTF3 MK-5's. So I guess I'll try corner with TV and opposite corner w/ bookshelf to the right of window.

With identical subs I read that you gain match.

I know after Audyssey you want subs ideally within +\-3 - how would I best gain match using only Audyssey?

Do you think this would work-

1. Put Audyssey mic at MLP
2. Hook up one sub in middle of room and run Aud on sub only unti I get like -3
3. Then hook up other sub and run Aud on sub only until exact same -3 ideally
4. Hook up subs in final location and then because two add 3db... Aud will hopefully show 0 for sub trim

Would that work? Or is their easier way?

* I don't have SPL. My AVR does have XT32 with sub multi eq.

 

[craig john]

Thanks Derrick, I don't think I level match if they are identical? They are both HSU VTF3 MK-5's. So I guess I'll try corner with TV and opposite corner w/ bookshelf to the right of window.

With identical subs I read that you gain match.

I know after Audyssey you want subs ideally within +\-3 - how would I best gain match using only Audyssey?

Do you think this would work-

1. Put Audyssey mic at MLP
2. Hook up one sub in middle of room and run Aud on sub only unti I get like -3
3. Then hook up other sub and run Aud on sub only until exact same -3 ideally
4. Hook up subs in final location and then because two add 3db... Aud will hopefully show 0 for sub trim

Would that work? Or is their easier way?

* I don't have SPL. My AVR does have XT32 with sub multi eq.

Easier method: Set the gains on both subwoofers at identical points. This should get you very close to being gain-matched, depending on the accuracy and repeatability of the gain controls on your particular subs.

Harder method: As you describe above, but with the Audyssey mic nearfield to the sub, (within 6".) It needs to be the exact same distance when you replace the 1st sub with the 2nd sub. You'll also want to set the levels to about 85 dB nearfield, so when you place the subs back in their in-room positions, and you measure at the LP, they're within the prescribed range necessary for your Audyssey run. This may take some experimentation but this is the more effective and more accurate method.

Craig

PS. After you run Audyssey, if it sets different trims for each sub, you are no longer gain-matched. In that case, what I do is "split the difference." IOW, if one sub is set to -3 and the other sub is set to -6, I split the difference and set them both to -4.5.

 

[derrickdj1]

Either way should give you very goood results. Let us know how it works out.

 

[Alan P]

Yup, after gain matching, do this.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Set the gain on both subs to the same level - around 12:00-2:00 on the gain knob is a good starting point (just a starting point, gain structure can vary greatly from one manufacturer to another). Set phase to "0" on both subs for now.

1. Connect sub #1 only and place it at the MLP
2. Do the sub crawl to determine the best position for sub #1
3. Place sub #1 in that position
4. Connect both subs and place sub #2 at the MLP (with sub #1 playing as well)
5. Do the sub crawl to determine the best position for sub #2
6. Place sub #2 in that position
7. Playing the AVRs test tone, adjust phase on one of the subs until you get the maximum SPL at the MLP (could be variable or a simple 0/180 switch) (if you have SubEQ HT, skip this step)
8. Run Audyssey, first mic position only, and "calculate"
9. Look to see where Audyssey has set your sub trim, you want it to be around -6db to -8db ideally
10. Adjust the gain on both subs by the same amount up or down as needed
11. Repeat 8-10 until you get the sub trim around -6db to -8db
12. Run the full Audyssey calibration
13. Set all speakers to "small"
14. Set all crossovers to 80hz (or, if set higher than 80hz by Audyssey, leave them alone)
15. Bump up the sub trim by 3db to 6db to your preference
16. Enjoy!

 

[nalthien]

Yup, after gain matching, do this.

You might want to create a post with these instructions and add it to your sig with the other things; I've probably seen you post them 10 times in the past month--and I'm sure I haven't seen all of them.

 

[Alan P]

No room left in my sig, and it's a simple copy/paste...but, yeah, it does get posted a lot.

 

[Red99]

No room left in my sig, and it's a simple copy/paste...but, yeah, it does get posted a lot.

Ask to have a stickie made at the top.

 

[Alan P]

Woah...never thought anything little ol' me posted would be considered "sticky-worthy".

 

[nalthien]

Woah...never thought anything little ol' me posted would be considered "sticky-worthy".

Do you mean, "little ol' dual T-18 owning, tweaking every week (or day) me"--because, when you think about it that way, it makes sense.

 

[DaveyMac]

Thanks Craig! Thank Alan! Et al

Alan, if u do copy those instructions again I think you could actually, put first sub at MLP, then place second sub at best sub crawl location.. Do crawl again and put sub 1 (who's been at MLP the whole time) in the second crawl position. That would simplify it.

Unfortunately I can't just put gains at same place though.. My hsu gain knobs are insanely sensitive - they go from nothing to way beyond a bad -12db Audyssey run with almost know movement of knob.

So if my subs are next to wall in corner, should they point at wall or MLP. They won't be a foot from wall.

 

[DaveyMac]

Also, I'm getting a spl meter tomorrow.

Is this viable:

I have a test zone cd with different frequencies. Could I play like the 20, 40, 60 and 80hz tones, checking how much spl each registers with different sub placements? And then just go with what place gave me the most output?

And when I have a BD playing, when I set the knob to 0 (I usually have it around -15) is 0 'reference'? And is '0' / 'reference' approx 75 DB or 80 DB?