1st Waterfall

**gocitygo** · **10-02-09, 02:38 AM**

Is there anything wrong with the waterfall? Nothing from ~106Hz to 200Hz.

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**Wayne A. Pflughaupt** · **10-02-09, 03:11 AM**

Welcome to the Forum!

Known bug in the program. The graph is set for linear mode, not logarithmic. Click on the "Freq Axis" icon, top right of the screen.

However, your signal level is so low above 100 Hz, don't expect to see much of anything useful.

Regards,
Wayne

**gocitygo** · **10-02-09, 03:27 AM**

Thanks Wayne. Redo with semilog. Any comment/suggestion?

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**brucek** · **10-02-09, 08:35 AM**

Quote:

Redo with semilog

Actually it's log, since the vertical axis is expressed in decibels.

If you are using a sub equalizer, you might attempt to reduce the ringing around 50Hz. Overall, it's quite good.

brucek

**gocitygo** · **10-02-09, 09:02 AM**

Thanks for the comment.

Too bad I don't have sub equalizer. Would it helps if I reduce the sub vol a little?

**brucek** · **10-02-09, 12:19 PM**

Quote:

Too bad I don't have sub equalizer. Would it helps if I reduce the sub vol a little?

No, the room is causing the ringing, not the sub level. You either relocate the sub or equalize it to remove peaks and ringing.

brucek

**Wayne A. Pflughaupt** · **10-02-09, 12:28 PM**

Quote:

gocitygo wrote:

Too bad I don't have sub equalizer.

You almost don't need one. I haven't seen many people able to get response that good even with an equalizer! Its so good I have to ask, are you applying any smoothing? There shouldn't be smoothing on subwoofer graphs. If your sub has enough headroom, EQ could get your extension a bit lower, down to 25 Hz. That would make an audible improvement, especially with movies. It's possible you could eliminate the dip at 60 Hz as well. It would also give you the option for dialing in a house curve, if you were interested in that.

Regards,
Wayne

**gocitygo** · **10-02-09, 07:05 PM**

Hi Wayne, are you referring to the smoothing under trace adjustment? Thank you.

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**Wayne A. Pflughaupt** · **10-02-09, 08:08 PM**

Yes, that would be it. Like I said, it's amazing response you have.

Regards,
Wayne

**gocitygo** · **10-02-09, 08:23 PM**

Wayne, thanks for the compliment. Still got a lots to learn from Master Sifu

. Thank you.

Back to waterfall chart, are there any numbers that we are looking for to determine good/bad waterfall plot? i.e. small peaks at 45dB @ 300ms?

Quote:

Wayne A. Pflughaupt wrote:

Yes, that would be it. Like I said, it's amazing response you have.

Regards,
Wayne

**venkatesh_m** · **10-05-09, 03:52 AM**

gocitygo,

I believe it would be to bring levels down to floor noise (50dB?) before 300ms.

brucek,wayne,

Pls correct me if this info is wrong.

**Wayne A. Pflughaupt** · **10-05-09, 10:27 AM**

This post should shed some light on the subject.

Regards,
Wayne

**gocitygo** · **10-06-09, 09:15 AM**

Thanks. Great to see fellow Malaysian here.

Quote:

venkatesh_m wrote:

gocitygo,

I believe it would be to bring levels down to floor noise (50dB?) before 300ms.

brucek,wayne,

Pls correct me if this info is wrong.

**gocitygo** · **10-06-09, 09:17 AM**

Thanks again.

Quote:

Wayne A. Pflughaupt wrote:

This post should shed some light on the subject.

Regards,
Wayne

**Low-Q** · **10-13-09, 04:49 AM**

My guess regarding ringing or standing waves in the room is not possible to EQ away with good results. I believe its better to find another spot for the sub, or use 2 subs placed at the right spots. Standing waves will allways be there even if you EQ it a bit. You can also use absorbents to reduce the problem. One way is to make another enclosure with a slave in it that is tuned to the same frequency as the standing waves. It will start to oscillate with a given delay so it partially will terminate the standing waves between the parallell walls in the room depending on its Q value. The terminator should be placed at places where the standing waves are at its highest level in the room, and in a place that makes it most suitable sound in the listening spot.
the slave can be a normal subwoofer driver which you are altering its Q with a variable resistor which is connected in parallell with the driver terminals. You must find the right Q to suit the Q of the room. The higher the resistor value is the greater the Q is of the subwoofer slave. Maybe you need several of these terminators to reduce standing waves at 50, 100, 150, 200Hz etc. The lower the frequency is the bigger slave you need. These slaves can also be active if you manage to give it the approperiate delay, level, and Q.

Br.

Vidar

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