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Yea my area was so small I just went for first reflections and evenly spaced the other 4 from it. Measuring will probably tell you some things about it though. Are yours 2"? those are nrc of 1.0, the 1" is less so its not 100% absorbtion.

Funny reading through the sub/bass forum guy wants 2 subs for 5000$, because if you spend 5000$ is HAS to be good right? id bet you have maybe 1500 tops into these 2 tuba ht's. Someone I know just recently upgraded from a pair of 4000$ RSL subs, Has the perfect place to hide some DIY subs that would kill most things besides a JTR 4000. I just dont see the whole "I want a pretty sub" thing. When the lights go out and the movie starts all I care about is that I cant localize a crap ton of bass lol, plus...gloss black reflects light. Sorry for the tangent, just needed to get that off my chest.
Probably under a grand in the two THTs...

I know what you're trying to say about the guy wanting to spend $5000 on subs. But, in all fairness you don't know what his space is like. Or, if he has any room treatments. And, typically room treatments don't help bass unless they are VERY thick and floor to ceiling.

DIY isn't for everyone. Some people have WAF to consider; other people just like their stuff to look nice with the lights on.

I had gloss black NHT speakers for years, never had any reflection issues. Especially with the lights out, as you said.

Just something to keep in mind.

Typed on a tiny keyboard, excuse any typos
 

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Thanks for the thread referral. I'll dig through that and see what's what. I'm pretty good at deciphering forum info/misinfo and look forward to that learning curve. As far as tangible reassurance, I'm most excited when I have a problem and then I have that "Ah Ha!" moment, so I think there are still peaks to this process. And just for clarity, I'm not planning on making the compromises for infrasonic room treatment. I'll be at DSP and possibly some placement changes to get it optimized for those type of adjustments. But, like you, I am really curious if I can achieve the sub 20hz response that was quoted on the BFM THT page. I know I can feel pressure on my ears without hearing anything early in the sweep on REW, so I hope to have some graphs to back it up soon.



Oh yeah, I can hear echos created at the MLP, from all 7 channels, and terribly bad when I am close to the wall and talk at a reasonable level. There are times that the center channel dialog is very taxing just from the sharpness of the echo. I do have 3 bundles of OC 703 waiting, but want to base line before sprinkling them about, even at known good locations like first reflection points.
I had the same problem in my HT. I did have sweeps done before I put my panels up. I ended up building 12 panels, that are 2" thick, with 1.75" off the wall. It helped, a lot. But, I still think I need at least 6 more. But, they're really easy to build.

My room is so wide I didn't worry about first reflection points, but you should. I want to put 3 directly behind my L/C/R. I would recommend that also.

Typed on a tiny keyboard, excuse any typos
 

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Probably under a grand in the two THTs...

I know what you're trying to say about the guy wanting to spend $5000 on subs. But, in all fairness you don't know what his space is like. Or, if he has any room treatments. And, typically room treatments don't help bass unless they are VERY thick and floor to ceiling.

DIY isn't for everyone. Some people have WAF to consider; other people just like their stuff to look nice with the lights on.

I had gloss black NHT speakers for years, never had any reflection issues. Especially with the lights out, as you said.

Just something to keep in mind.

Typed on a tiny keyboard, excuse any typos
I suppose you're right. Everyone's different with different budgets and skills. Just drives me nuts lol
 

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Discussion Starter #84
I'll try to figure my total cost on both THTs and post that up too, for those wondering. Knowing the ballpark of how much I've spent, I can easily say that the value FAR exceeds monies spent!! Still want to watch The Dark Knight and a few others to really feel these out.

As far as reflection points and such, I have actually created a little "horn" out of the THTs for my mains. The way that they sit beside the mains, I have really improved the low frequency response when listening to 2 channel music from them. Purely by accident and I'm sure not without consequences that I have not picked up on yet, but kinda cool anywho. At the MLP, the speakers sound almost like cupping your hands behind your ears to listen. Again, I have not had much listening time---->tweaking time, so still have work to do.
 

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Discussion Starter #85 (Edited)
Yea my area was so small I just went for first reflections and evenly spaced the other 4 from it. Measuring will probably tell you some things about it though. Are yours 2"? those are nrc of 1.0, the 1" is less so its not 100% absorbtion.

Funny reading through the sub/bass forum guy wants 2 subs for 5000$, because if you spend 5000$ is HAS to be good right? id bet you have maybe 1500 tops into these 2 tuba ht's. Someone I know just recently upgraded from a pair of 4000$ RSL subs, Has the perfect place to hide some DIY subs that would kill most things besides a JTR 4000. I just dont see the whole "I want a pretty sub" thing. When the lights go out and the movie starts all I care about is that I cant localize a crap ton of bass lol, plus...gloss black reflects light. Sorry for the tangent, just needed to get that off my chest.
Yes, mine are 24X48X2. No worries about the rant. I feel the same way when people want to go on about all their cool equipment, and can't say anything except brand "X" at Best Buy is the best thing since sliced bread.

And for the record, since I had some of the misc supplies already (screws, gasket material, wire, etc) I am in both cabinets for under $600 thanks to refurb drivers and going with the cheaper wood option. That doesn't include the $240 I gave for my XLS1502, but I caught that on a steal of an open box deal from Sam Ash. Not too shabby for what I have in it I'd say.

Also, here is a sweep that I got with the XT32 mic with the THT's. I know that the db is off, but the response might be accurate. Curious to see what results I'll get with a calibrated mic. 1/6 smoothing applied
 

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FTR for REW sweeps, if posting for analysis, post unsmoothed results . . . because: "they" said so.

yes, the brain will do smoothing for us to some extent and it does "look better "

and it a shame we just can't post the mdat files at AVS but you could always use dropbox if working with someone who wants to "play" with the data.

that's how I got to where I am, for now

get the right mike . . .

i went from the first with that hole at 36 hz to pretty good given +/- 5 db with no filters, just sub distance tweak , mains distance settings and xo adjustments.
and no smoothing
 

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What was your sub distance tweak? I've never thought to tweak that.
 

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What was your sub distance tweak? I've never thought to tweak that.
Adjusting the distance of your subs to help smooth out the response around the crossover region.


Just run a sweep of a speaker set to small (bass managed) - I use the Center speaker. Then (usually) add some distance to the subwoofer - run another sweep - and see if it filled/smoothed any problems in the crossover region. After 100's of REW sweeps I almost always have to add 100-130cm to my subs distance to fill in a large dip around 70-80hz I always have post Audyssey
 

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hmm, crazy, Ive never thought that would do anything, thought it was more for delay/timing then changing freq response... so adding about 3 1/4 - 4 1/4 feet to the sub distance is where you are seeing gains. I have a umik and REW...may give it a shot tonight.
 
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@trilkb
according to the EQ gods, both subs must get the same distance changes .

however
initially XT32 and the Sub EQ set my 2 subs to 23.9' and 19.6'.
very interesting in a room only 10.5 x 9.5 ish . . don't you think?

fired up REW and began slogging thru many sweeps - you WILL make a log of initial settings and of of every change

like getting an eye exam - which is better #1 or #2 ? you need to see what is working . . .

(insert #1 vs. #2 joke here)

the end result was what i posted.

sub 1 in front , like only about 7ish feet from the mlp, right corner, pointed at the ceiling, the 30" THTLP : 12.7 feet setting

sub 2, 24", directly behind my seat, on the floor pointed into the lower left rear corner, loading at about 18" : 11.0 feet.

" hmm, crazy, Ive never thought that would do anything, thought it was more for delay/timing then changing freq response... so adding about 3 1/4 - 4 1/4 feet to the sub distance is where you are seeing gains. "

you'll be at it for a while . . those changes may or may not work

i did try changing each sub by the same distance but it wasn't going to work that way in my room.

but your room is your room

may the good results be yours. .
 

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hmm, crazy, Ive never thought that would do anything, thought it was more for delay/timing then changing freq response... so adding about 3 1/4 - 4 1/4 feet to the sub distance is where you are seeing gains. I have a umik and REW...may give it a shot tonight.
Yes with my particular setup at the time (4x SVS PB-2000s with PSA MTM-210s) I would consistently get a large dip around 70-80hz post Audyssey. Adding around 100cm to the Subs distance would greatly reduce it. Each room/system is different though, but a lot of people have used this technique to get a smoother response,.


Another "tip" I picked up from Mark Seaton - which also helped further smooth out my response - was that if you have both subs upfront and equidistant to the MLP, try running both subs off 1 SW Pre-out by using a Y-splitter.


Honestly for me ,the biggest change came from using REW to find the best seating position. My old MLP was in a huge null. When we got a new couch I ran a bunch of sweeps to find the smoothest pre-Audy result- I ended up being about 50cm further from the TV , but the response was much better (but still far from perfect)
 

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Discussion Starter #92
Yes with my particular setup at the time (4x SVS PB-2000s with PSA MTM-210s) I would consistently get a large dip around 70-80hz post Audyssey. Adding around 100cm to the Subs distance would greatly reduce it. Each room/system is different though, but a lot of people have used this technique to get a smoother response,.


Another "tip" I picked up from Mark Seaton - which also helped further smooth out my response - was that if you have both subs upfront and equidistant to the MLP, try running both subs off 1 SW Pre-out by using a Y-splitter.


Honestly for me ,the biggest change came from using REW to find the best seating position. My old MLP was in a huge null. When we got a new couch I ran a bunch of sweeps to find the smoothest pre-Audy result- I ended up being about 50cm further from the TV , but the response was much better (but still far from perfect)
That graph is pretty dang level to me! No huge peaks or nulls, I'm sure 90% of home theater users would be lucky to achieve a sweep like that. Perhaps myself included;)
 

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Discussion Starter #93


Got my UMIK and REW up and running. Here is the initial measurement with no eq, no Audessy, and no smoothing. Not the worst thing to start with I suppose. I did not have any time to work on changing the locations of the subs. Maybe this weekend I'll have some time at the house that is quiet and I can check response across the seating area and see what I can do.
 

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you should also post in the audio set and chat section with your own thread

you need to change your left margin to read by "5"'s, i.e. 50-55-60-65, try adjusting the overall scale, gives a more detailed picture

and for subs the range preferred (and correct me if I'm off a few Hz) maybe 18 to 300

are you using the ASIO4ALL or the Java setting . . .?

HTh
 

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Discussion Starter #95
you should also post in the audio set and chat section with your own thread

you need to change your left margin to read by "5"'s, i.e. 50-55-60-65, try adjusting the overall scale, gives a more detailed picture

and for subs the range preferred (and correct me if I'm off a few Hz) maybe 18 to 300

are you using the ASIO4ALL or the Java setting . . .?

HTh
I am using ASIO, it took a minute to get it worked out, but I have it active and working properly.

I was close on the ranges, it's 15-300 hz and 45-105db. Not sure on the db resolution, I'll have to look into that and see. From memory, most graphs I've looked at don't have 5hz increments, but I could certainly be wrong. I was trying to quickly set that by memory. Wife and kiddo were on their way home while I was assembling the mic boom for the first time. Just figured I would share an initial graph since I have not updated for a minute or two. I will also follow your advice for setting up a calibration thread over in the setup section.
 

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Got my UMIK and REW up and running. Here is the initial measurement with no eq, no Audessy, and no smoothing. Not the worst thing to start with I suppose. I did not have any time to work on changing the locations of the subs. Maybe this weekend I'll have some time at the house that is quiet and I can check response across the seating area and see what I can do.
Not too bad. That's a pretty ugly dip though. Be interested in seeing what Audyssey does. And, what it would look like with them in opposite corners.

Typed on a tiny keyboard, excuse any typos
 

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the dip may be too narrow but time will tell
 

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That was mine with just audyssey. The only big dip is around 60-65hz which maybe messing with sub distance could help.... the other 2 at 23 and 27 Hz I don't know if they are worth messing with. I like the "house curve" from about 20-35hz I got lol. After mini dsp non hd I lost a TON of bass. Like 10db across the board. The HD shouldn't have as big of drop, but I could also be using it wrong.
 

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That was mine with just audyssey. The only big dip is around 60-65hz which maybe messing with sub distance could help.... the other 2 at 23 and 27 Hz I don't know if they are worth messing with. I like the "house curve" from about 20-35hz I got lol. After mini dsp non hd I lost a TON of bass. Like 10db across the board. The HD shouldn't have as big of drop, but I could also be using it wrong.
You shouldn't be loosing bass with a MiniDSP.

Typed on a tiny keyboard, excuse any typos
 

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Discussion Starter #100
The weekend has been pretty good to me thus far, got some quiet time last night in the house to run sweeps and do a little trial and error. I first wanted the check the response of the subs at the mouths and compare against the 18" gap exit from the wall. Conclusion: 12" gap was very close to the same db and response as the 18" gap when measured from the MLP. The 12" gives me more room beside the screen for larger mains, so I made that my final position. Even with 24.5" wide cabinets, they are simply too big to try a lot of different placements. Because of the layout, I can't do opposite corners, mid-walls, or 1/4 walls. Opposite front corners is going to be as good as it gets for that battle.

Besides, my MLP dip is included with the horn mouth measurements, so there ya go! Looking at Bill's website, the 24" version shows a kind of dip in the same region as my measurements, so I'm probably just cabinet limited for that. Since the dip is above the box tuning, maybe some DSP could correct it, but I'll do some subjective testing to see if it even bothers me. I also plan to wait a bit before deciding on a miniDSP at this point. Here is what I wound up with after messing with placement.




But, since subs are part of a system that includes crossing over to the mains, I wanted to try mtg90's integration documented on this thread. I will confess, the only thing I was able to manipulate was the distance tweaks, so optimization was not critically explored. I went through the steps and then ran Audyssey and found that changing sub distances only created phase problems and resulted in poor graphs. One thing that smoothed the crud out of the crossover region was to set Audyssey to flat and bypass front mains.



I"ve yet to watch a movie since doing this. I am typing this out listening to Clint Eastwood by Gorillaz and have been listening to music most of today and really am enjoying the clean bass and how it all sounds together. I have had the opportunity to demo these beasts for a couple of friends and they have not failed to impress!! For absolute value from a 15" driver, I'm not sure how anyone could do much better!!
 

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