Home Theater Forum and Systems banner

41 - 60 of 69 Posts

·
Premium Member
Joined
·
6,711 Posts
It would be better to connect the soundcard to your av processor so that you see the effects of the processor's crossover, the sub's own crossover would then be disabled or set to its maximum. You should set your sub's volume control by using a 75dB test signal from your processor or test disc, setting the processor level trim to zero then adjusting the sub's volume control to get 75dB at your listening position.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #42
I don't have a receiver anymore. It is gone. The subwoofer has no adjustable crossover on the back. It is 80Hz crossover.
 

·
Premium Member
Joined
·
6,711 Posts
Looking at the manual of your sub it does not have a crossover filter, it relies on the processor/receiver to take care of that which is why your measurement does not show the roll-off of a crossover. That deep null is probably related to the mic position, was it on the centre-line of the room? If you move the mic off-centre does the null become shallower?
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #44
When I set the volume of the subwoofer using the test disk, playback from my subwoofer is extremely loud from the soundcard. I would not recommend anyone use the XA2 test tones. Something went horribly wrong there, and I refuse to touch it again.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #45
The mic was located on the head rest of the center seat front row, inside a slinky pointing upwards. It is the center of the room. I will try moving the couch.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #46
Moving the seating forward seems to make little difference. Placing the mic at the left or right seat does. This is with the subwoofer in the right corner again where the 50Hz peak is lower for the center seat. The couch was moved forward about one foot.
center and right.jpg
 

·
Super Moderator
Joined
·
9,271 Posts

It would be better to connect the soundcard to your av processor so that you see the effects of the processor's crossover, the sub's own crossover would then be disabled or set to its maximum.
I don't have a receiver anymore. It is gone. The subwoofer has no adjustable crossover on the back. It is 80Hz crossover.
Looking at the manual of your sub it does not have a crossover filter, it relies on the processor/receiver to take care of that which is why your measurement does not show the roll-off of a crossover.
That would sure explain why everyone’s been able to localize the sub so easily. I suggest getting an outboard crossover...

Moving the seating forward seems to make little difference. Placing the mic at the left or right seat does. This is with the subwoofer in the right corner again where the 50Hz peak is lower for the center seat. The couch was moved forward about one foot.
Once again, try moving the sub down the wall away from the corner a few feet. Try it in 1-ft. increments in each direction and see if that null disappears.

Regards,
Wayne
 

·
Registered
Joined
·
47 Posts
I don't mean to hijack your thread, but holy cow, nice setup! Can you pass me the popcorn? :T

Geez, I'm glad just to hear my DIY speakers play ... maybe someday I'll graduate to a dedicated room like you have.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #49
That is where my subwoofer ended up at in HT version 1.0 before this one and exactly how I did it. I will try moving away from the corner slowly and see what happens. I have to correct myself from before. I was looking at the dial upside-down. The volume was up about 25%-30% for the measurements. I plan to use a pre/pro later so I think I will be alright for now. The XA2 has it's own bass management. The pink noise on the XA2 after setting everything to zero sent my AVR into safety shutdown mode. It caused my mono amps to temporarily click off directly hooked into them, so I am not going there again. I will only use DVE from now on. I already discussed a new AVR and they are in agreement that a universal remote is not worth the cost of simply buying a new receiver, and one that is better compatible with a new plasma, has more features etc, so all is alright there. I plan to use my televisions variable output for the setup in my room anyway which is hooked up to a two channel amp.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #50
This is the subwoofer on the back wall again where I started last time I was taking measurements in the previous thread. I still have that valley around 25Hz there. back wall.jpg

When I move the subwoofer along side the wall up front. which way do I point the driver? That part has always confused me. If I used the back wall, I would want to use the front wall also...
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #51
Here are a couple more using the method of placing the subwoofer on the center seat and moving the mic.

Mic sitting behind my equipment rack (blue) in the back center of the room and the mic sitting on the floor of the front center of the room (purple).

behind equipment rack and bellow screen.jpg

Mic sitting on the right wall after adjustments (green) and mic sitting between the right tower and center channel (black).

right wall front and between right and center.jpg
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #53
Thank you again Wayne. This has been a great learning experience. THX Tech Level 1 training is only a couple months away now but I feel like it has already began.:nerd:

I will order the BFD then now. :sweat: What happens to a waterfall like this when a larger subwoofer is introduced? Do you you know where I could find a nice example?

waterfall.jpg
 

·
Super Moderator
Joined
·
9,271 Posts

What happens to a waterfall like this when a larger subwoofer is introduced?
It will show an increase in signal level, and ringing, below 30 Hz. The signal level will be due to the bigger sub’s better extension; the ringing will be due to the fact that it’s next to impossible to treat ringing that low.

Regards,
Wayne
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #55
When I use the set target level button, REW sets it to a 83.3 target and then suggest a 0.250 BW versus with the 75 target at 0.143 BW. It sets both filters at the same peak at 49.66 and suggest the same level of -8.8 gain for each. I did this without adjusting the input volume of the mic this time which seemed to have been incorrectly having to think I was getting further extension with the higher target. This was the difference between setting the level on the back of the subwoofer, versus the THX switch setting.

When I assign the filters later after measuring through the BFD, do I use the 75 target or the suggested 83.3. Should I raise the volume to 85 if it still suggest the 83.3? The help area says that the target is important for setting the correct gains and width, and I keep getting all kinds of error messages with the 75.

Also..I am supposed to set the input level of the mic using the 75 target and let REW determine the appropriate target by that setting? My input volume is rather low with the 83.3 target but I presume this is to prevent my mic from clipping?
 

·
Premium Member
Joined
·
6,711 Posts
The target level figure that REW determines is its best estimate of the level that the response would show if the peaks and dips of the room were not present. It has no bearing on the mic level, you only need to set the mic level once when you do the input level calibration and not adjust it afterwards. The input level setting allows some headroom during measurements to provide for the effects of room resonances and avoid clipping, as you presumed.

After you have allowed REW to set the target level leave it there when finding peaks, assigning filters and optimising peak gain and Q.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #57
Thanks John. That makes perfect since to me now. The BFD just arrived and so did the accessories also. :yay:
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #58
I gave it a try with the filters with the measurements then did some listening. It didn't sound right to me the way I was doing it. I went and took meaurements using a macro while I was holding the mic in front of me. I then took filters and applied those to that result. I did all this after setting up the inputs, and then changing it to the 85 target. I uploaded my filters boosting slightly around the 55Hz area, and making a few adjustments here or there with the peaks. This is a look at measured and predicted response.

filters.jpg

Measured

measured.jpg
 

·
Premium Member
Joined
·
6,711 Posts
As you are measuring without a crossover your target should be flat rather than a sub crossover curve (change the shape in the Target Settings). That would reduce some of the cuts.
 

·
Registered
Joined
·
1,405 Posts
Discussion Starter #60
I will give it another try. Should I try and add the boost again? It looks close to where REW wants to remove a peak.

crossover adjust.jpg

Should I be doing this in the 83.3 target? Is my crossover wrong? My room is causing problems?

This is the mains again with a 75dB target, subwoofer with the 85dB target.

mains and subwoofer.jpg

mains waterfall.jpg
 
41 - 60 of 69 Posts
Top