Finally have time to do my PC-12Plus FR. Using realtrap.com's test tone and pink noise armed with SPL meter.

http://www.realtraps.com/test-cd.htm

Here's the graph. Anyway, will try other s/w as well to compare the result.



As you can see, there is a serious issue from 40Hz to 48Hz as it dips real low. Abt -26dB difference    The 'valley' is difficult as the PEQ only tackles peak. As you can see in this graph, the peak (28Hz) is being 'subdued' a bit. Any advice would be welcomed 

At 16Hz, it starts to roll off 'dramatically', hitting 60dB at 10Hz, which is the same reading that I got when 46Hz tone is played. Only at 47Hz, the reading flipped to 50dB. It shot up to 61dB for 48Hz. There must be something very wrong with the room acoustic or something is messing with it . Need to find out 

When I have time, I'll do some 'tweaking' with the room. Then, re-do the graph again.

Oh yes, to get the 70dB reading, the volume level is at -33.5dB on my 1900. Crossover setting is at 80Hz.

wth, you buy 100kg/m3... gila heavy. how many inch thick you wanna make?

btw, the table is for 2" thick and does it mean double the coeff. if 4" thick?

I have shifted my sub to the corner of the room instead of 1/3 of the room. This would be the single easiest way.

I have acoustic foams at first reflection point, behind the front as well as at the back of the room.

Now, time for another graph. Will post after I am done with it.

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Update :



I have shifted the PC-12Plus to the corner of the room, right at the back of my Klipsch. The Klipsch have to be brought forward by abt 1' 8" to let the  SVS in. Luckily, it didn't block the screen. Now, the Klipsch is parallel with the center spkr.

It is better and still needs to some improvement. I had removed the port block and set it at '20Hz' instead of previous '16Hz' with a port block. More to come. GTG

still see the dip... can it be the fault of the subwoofer itself??

still see the dip... can it be the fault of the subwoofer itself??

No, these are room problems.

I wish we could check it with Audyssey. Audyssey has 8 times more resolution in the low frequencies just to improve these points. While it cannot fix the drop, it will balance it out.

I would suggest this, put the subwoofer in ur primary position and play the 40Hz, move around the room with the SPL meter to see if you can improve it. Then re do this. As pierreye suggested this is the easiest way.

I guess that explains why I have to increase the level of the sub by more than 20 db just to feel the punch especially when playing music.

I try moving the sub around to the other corner and not much different and there is no other place where i can put this sub in my living room so i guess i have to live with it.

Unfortunately, my 1800 does not have Audyssey 

Hey, didn't u get the SVS EQ device? That should help greatly in ironing out the sub freq curve.

Anyway, did you download ModeCalc to check on your room modes? It's here: http://www.realtraps.com/modecalc.htm

bro u didnt buy the spl meter? .. just try to do what htkaki did then it is much easier to solve.. if not u will get a hard attack like me last time during movies.. at the end found out i had +30db peak for certain frequencies

time for sky dragon? whistling.gif

  Yes, I knew that AS-EQ1 could help tremendously but it is selling like hot cakes. Have to wait for next shipment. ETA mid Sept if there is a unit to spare  If not another 1 mth wait. No need to crack my head doing this and that. Plug it int, fiddle with the mic and knobs. Voila...... 

The best option would be a complete treatment of the whole back wall since the length is exactly double the width of the room    Luckily the height is not 10. Else , I really need to shift to another room.

btw, how's your progress?  Really need a lot of time to do it which is 'luxury' to most of us.
Bro, IIRC he bought one. I guess he never utilise it    Peak is a serious no no.
Correct me if I am wrong. Even with Denon and Onkyo's current models (high-end models exempted ), it could not eliminate 'peaks' and 'valleys' effectively . Still room treatment is needed. Any Denon / Onkyo owners care to share their sub FR graph? 

  Yes, I knew that AS-EQ1 could help tremendously but it is selling like hot cakes. Have to wait for next shipment. ETA mid Sept if there is a unit to spare  If not another 1 mth wait. No need to crack my head doing this and that. Plug it int, fiddle with the mic and knobs. Voila...... 

btw, how's your progress?  Really need a lot of time to do it which is 'luxury' to most of us.

Correct me if I am wrong. Even with Denon and Onkyo's current models (high-end models exempted ), it could not eliminate 'peaks' and 'valleys' effectively . Still room treatment is needed. Any Denon / Onkyo owners care to share their sub FR graph? 

Oh yes, I will bring in PC-12NSD, PB-12Plus, PB-13Ultra and PC-13Ultra (reserved) in early Sept 2009.

SVS doing very well. Sub selling like hotcakes, EQ also selling like hotcakes.
Yeah, I agree it takes a lot of time, effort and experimentation. Tried the foams at 1st reflection point, got small difference. But I haven't had time to do much else.
The Audyssey MultEQ XT does help some. It won't give a perfectly flat graph, but it does help soften the peaks and valleys some. I did one before and after graph, will upload later coz it's at home.

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Added on August 4, 2009, 12:27 pmOh yes, I will bring in PC-12NSD, PB-12Plus, PB-13Ultra and PC-13Ultra (reserved) in early Sept 2009.