New THT build in Wisconsin

[MissileCrisis]

For the love of god don't play music through it before you stain it, it will never leave the house I love my T60 so being without a sub for 2 days while I painted it was tough. Best solution is have another BFM sub to tie you over (in case you ever decide you need 2 of these monsters).

[Radian]

Best solution is have another BFM sub to tie you over (in case you ever decide you need 2 of these monsters).

Sage advice, right there.

[howiez]

For the love of god don't play music through it before you stain it, it will never leave the house I love my T60 so being without a sub for 2 days while I painted it was tough. Best solution is have another BFM sub to tie you over (in case you ever decide you need 2 of these monsters).

Sage advice, right there.

You are both right, I have it near a corner for and I am reluctant to remove it. I have amp and driver to build a second (as was my plan all along), another tube of PL, and 1/2 of the 2.5 sheets of Arauco I need( I bought three 3 4x8 first go-round). SO if I can just nab 2 more sheets... WAF is doomed on the first, I wonder what she'll say to two end tables...

I am simply amazed at the 20-30Hz content. Bill, I'm not sure you've used enough adjectives to describe these beauties. I've made several passes with test tones and my trusty RS analog SPL meter. I took my levels with C-weighting on, which i think was correct per some feedback in these forums. However, there seems to be too much content below 30Hz I never heard before. Maybe that's the folded horn benefit? Simple things like a live football game off air have incredible low end noise which makes me think I've EQ'd this thing awfully. Movies sound incredible, so right now have 2 presets on my DSP1124P, one with the low end scaled back a bit. We'll call it "late night theater". I'm guessing this is where my 'house curve' would come in, does that mean make it flat and then adjust to taste?

I have some graphs from REW I'll try to post, I'm very noobish and not grasping it so far. Or perhaps I have grasped it and it's just that odd. I have an incredible suckout at 30Hz. At first I thought t was my choice of drivers as I didn't FTP to a T at the start, but had plans to circle around. I have since acquired the recommended Dayton RSS390HF-4 and short of gaining 20-25Hz content (according to REW) I still have an amazing suckout at 30Hz. So as a check I put my old Klipsch KSW-12 back in the corner and tried to match levels and setup as best I could. Lo and behold I have the same suckout. So now I have to presume it is my room / placement. I do intend to put the pair (when second is built) of THT's along parallel walls once they become end tables. But for now I was going for the corner load and the gain (which I'm thinking I have zero need for now with their efficiency.)

[MissileCrisis]

There are listening positions in my room that look like my t60 is high passed around 35 hz, move to a different spot and monstrous lf, trust me when I say it's the room. Have fun moving the sub around such that the most even response is at your listening position as all small heck even medium rooms have pesky modes. If you're at all concerned, do a measurement 6 inches from the mouth with the sub in the middle of the room, should decently ignore room reflections and should give you a decent idea of cab response sans walls.

[Tom Smit]

It's the room.
Also, in regards to LF content during the football game,etc., it's the lack of total frequency control during sound editing at the original source (not your system). As you have done, two EQ curves will do the trick.

[howiez]

So here are my graphs, hopefully i've captured enough and sensibly. Although it sounds like location, location, location! Hopefully i can get my legs on soon and move it to a wall and try again.

So for a reality check, my Klipsch KSW-12, 12" ported sub, 440w(peak) bash amp. Well over 12 years old and it has served me well.

My 'test' driver, and old RS 18" sub. I figured someone would pick it out in the pictures by size alone. I just had to try, my teenage sons really wanted to blow it and tear the cone. Actually it performed OK until I could get my beloved Dayton in there. Definitely not the low end of the Dayton, but frankly it worked decent, just can't crank it to 11.

Finally the Dayton RSS390HF-4 , same 30Hz suckout without EQ first.

Again the Dayton RSS390HF-4 , with EQ got more 20-25Hz but suprisingly the suckout? Can't figure that since I measured same dB at 32Hz.

[Bill Fitzmaurice]

It's the room.
Also, in regards to LF content during the football game,etc., it's the lack of total frequency control during sound editing at the original source (not your system).

+1. Their monitoring doesn't go as low as yours does, so they can't hear what you do, and they don't know enough to high pass filter out the noise. The Weather Channel never used to high pass at all, and not only could you hear low frequency noise in the studio, you also could hear the occasional truck passing by outside. BTW, the 32Hz suckout is a textbook boundary reflection null.

[howiez]

Here is a side by side of my 18 on it's way out and the 15 about to go in. Amazing motor structure by comparison. Then again it was a nice sub 20 years ago... Anyway it had to go, had to get the 15 installed.

[howiez]

I finally was able to tear it out of the living room to stain and poly. We took advantage of a warm fall weekend.
Pre-stain treatment on the outside, which I regret not doing in the mouth, which stained near black.
Bombay Red Mahogany IIRC, and three coats of Polycrylic water based clear gloss.

[howiez]

And a view in it's intended location, probably too far from the corner for any loading (right side of door is adjoining wall).
Hopefully I can find time this weekend to re-tune it, I feel like I lost a ton of output, but output is much smoother now..
I did do 4 coats on the top, hopefully beverages won't damage it.
And my improvised feet, made with 3x3 squares of 3/4" scrap plywood laminated, sanded, stained and poly'd to match.
The WAF went way up after she saw this, got pretty tired of the 'white elephant' in the corner before.

[SeisTres]

That far away from the wall, and forget about corner loading, you'll need to start to worry about cancellations, which is apparently at 30hz at your listening position. When I used to play around with moving my subs around in home, I finally decided that the corner was the most preferable place for it, so now I keep it in a corner and just eq my listening position.

And speaking about Eq, what's with the -20db from <45hz? There's a plenty of content even in music down to 30hz, and movies need that all the way down to 20hz. If your system can do flat to 20hz, I would definitely use that potential and eq the whole thing flat.

[Tom Smit]

The WAF went way up after she saw this, got pretty tired of the 'white elephant' in the corner before.

No doubt, with a cab like that!

[howiez]

I'll get a graph from the new position this weekend. I have a feeling I'll be moving back to a corner. It's smoother now, but I fear I've lost the bottom end. As for my graphs, I still have not mastered REW. What I did was manually 'flat' my Behringer DSP1124P by using test tones and a RS analog meter. I made several passes at each of 10 bands IIRC, 10Hz wide filters, matched them within +/-1 dB of each other if not right on. However, I still feel my meter is not picking up right. In the corner, that loading was monstrous, It shook the entire house, but you can see, it does dip below 45Hz, and of course that terrible suckout at 30.

Bill how do I correct a boundary cancellation? Is that due to me being too close or to far from the corner, or is it a room dimension thing? I that graph, my first positoin, I was about 2 feet from each wall parallel to one, pointing at the other. I had moved it anywhere between 2 and 3 feet from mouth to wall, and it all seemed the same to me. So a wavelength for 30Hz is about 37.5 feet, and a 1/4 wavelength then is 9.375 feet. Does that mean a wall, probably the opposite sidewall is about 10 feet away?

*EDIT* OK, you really have me thinking now. I measured and my THT was 13 feet away from the opposite side wall. My LR is 19'-6" x 17' with a vaulted ceiling 8' at the walls and 10ft in the peak. That is my ~9ft cancellation? I don't think my wife will let me tear the roof off with winter coming. What can I do? Please say build a second THT! (I have everything set aside except for two more sheets of plywood)

And I have another theory, question. My LR is rectangular, jutting off the rest of the house. The basement underneath is all solid concrete, and the THT is near an outside corner. Can I be getting reinforcement from the basement corner as well? The reason I ask is in the new position, i'm only 4feet from a corner, but it is midway along the long side of the basement. My lows are missing more than i expected there. I ran my same EQ drill to a new preset on the Berry, 20 and 25Hz are almost inaudible, and anything above seems overly loud. I know we hear more sensitively moving up the scale, but I don't remember the other position being like that. It was all BIG!

[Bill Fitzmaurice]

Bill how do I correct a boundary cancellation?

A null occurs when the reflection and the original wave arrive at the listening position 180 degrees out of phase. The cure is to move either the sub or the listening position, if not both. You can fill a null to some extent using EQ, but filling a null at one listening location results in creating a response peak in another. Rather than try to just fill in a null with EQ take the EQ down in the other frequencies as well to level response. Accept the fact that with only one sub the size of the listening position where you can get relatively flat response will be fairly small. Even response throughout the entire room requires at least two subs.

[howiez]

Thanks Bill, now I understand better. I was thinking it was 'everywhere' because the sub might be 1/4 wavelength of 30Hz away from the ceiling. So really it's my LP distance to a boundary and sub being equal. I've been measuring in one LP of two symmetrically placed recliners. I'll move my mic to the other and see what I get. Now maybe I can figure out how to EQ that bottom end up then.

Should I move my THT to the middle of the room and EQ with a SPL meter in/near the mouth to get flat first and then tune to taste in final resting place? I guess i'm wanting to get that 20Hz up near the rest of the curve. As SeisTres mentioned, I'm rolling off from 45Hz down, and it sounds like I could EQ that up to flatter?

Time to look at some more REW tutorials...thanks again everyone!