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This is a simple idea that came to me this evening. An in-room-response to help find that best possible flattest frequency response (in real time) while moving the sub around at the same time, while looking at the frequency spectrum, on the Spectrumlab display on the pc monitor.

I think this idea will also greatly reduce time in finding that location with single sub bass speaker or multiple of subs for the ultimate flattest response.

The idea suddenly came too me after, frustration :gah:with using (REW) Room Equalizer Wizard not that there’s anything wrong with the program software its just time consuming with moving the sub then running the frequency sweep which takes minutes this can way it can be cut-in-half.:T

It would help if you had an assistant to help you move the sub around and try all possible ideas like placing it above the floor will change the frequency response. In corner doesn’t do many favours unless it provides full flat response without too many dips. For me, I’m rather tough lifted the little sub up and carried it around the room while looking at the pc screen.


Anyway I made this rather quick video, no sound as its camera with video only! The film is Indiana Jones and the Last Crusade (1989). The Behringer ECM8000 microphone is placed at the listening seated position. The video is only 38 seconds long.

Spectrumlab Indiana Jones and the Last Crusade
 

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The idea suddenly came too me after, frustration :gah:with using (REW) Room Equalizer Wizard not that there’s anything wrong with the program software its just time consuming with moving the sub then running the frequency sweep which takes minutes this can way it can be cut-in-half.:T
Why not just use REW's RTA feature? :huh:

Regards,
Wayne
 

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You can also place you sub in the main listening seat and move the mic around instead moving the sub around.
 

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Discussion Starter #4
You can also place you sub in the main listening seat and move the mic around instead moving the sub around.
Thanks Sonnie, I was told over at avs. Why didn’t I think of that in the first place! Lift that sub up was fairly heavy, but I got a good workout at the same time.

I took another video with same software with pink noise playing from the dts demo music calibration set-up disc CD. Track 14 all-channels. I only used one channel with the remaining channels muted. Played the centre low end output to Eltax A12-R at the seated position, or rather on the sofa!

Moved the ECM8000 and there is slight loss connection on the XLR so you might see some 10Hz extreme on the waterfall spectrum, ignore that, that was recorded after trail and error. I had to fold some of the cable in my hand around the ECM8000 to keep the XLR stable.

The video runs for 5 minutes 18 seconds and yes its really like watching paint dry. :bigsmile:

Spectrumlab sub bass frequency test pink noise 10Hz to 120Hz

I’ll do another one around this time afternoon as I could do with some natural light, thou its a bit cloudy outside at the moment, expecting rain sometime to day. LOL

Anyway what do you think of the idea I think it’s the best thing since microwave popcorn.
 

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Discussion Starter #5
Why not just use REW's RTA feature? :huh:

Regards,
Wayne
There is an RTA on the REW? Why wasn’t I :gah:notified about these things before? :bigsmile:LOL

Where, where is the button for this action and does it record in the same way as spectrumlab or better?

Cheers Wayne, I'll have a look for RTA.
 

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Found it it’s under spectrum and looks like I need to find some settings for it. I need faster response time as it seems to be lagging in preset mode? I can see the octave division okay sorted.

Seem like you guys even threw in the kitchen sink, everything expert the dishwasher.
 

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I need faster response time as it seems to be lagging in preset mode?
The RTA feature is fairly typical. It simply presents the response graph in real time. It also allows you to display a static sweep measurement on the same plot for comparison.

Follow the info below on using the RTA:

To use the RTA feature of REW, you must first setup the levels as if you were about to make a standard response measurement.

This involves running the Check Levels routine for the mic at the listening position to 75dB and the Calibrate routine. You can even run a measure to have a reference on the RTA plot.

Then, select the Spectrum tab in REW and setup the controls as shown in the picture below.

Then, select the REW Generator and select Pink PN and start the signal using the play button.

Press the Red record button on the Spectrum page.

You can monitor your Input Level on the Spectrum page in the bottom left hand corner.

If it reads clip at any time (because you're moving the mic around when using the RTA), then simply turn down the REW input level a bit.

As an example, below shows a response measure I took (that gets transferred to the RTA graph), and the black line is the RTA plot itself. Now I'm ready to move the mic around and watch the black line change as the mic moves around.

Use the settings for the RTA as shown in the pic.



brucek
 

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Discussion Starter #8
Cheers brucek for that helpful information its all about the information.
 

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Discussion Starter #9 (Edited)
Star Trek IV spectrumlab FBQ2496 OFF/ON

An in-room frequency response of Star Trek IV The Voyage Home (1986) the one with the whales.

Here I’ve stretched the limit diy JBL 4645 as far as I can possibly take it, as I need to know where she can or can’t go in terms of frequency response and SPL db max with the new FBQ2496 parametric EQ settings that took me several hours a few nights ago.

Star Trek IV spectrumlab FBQ2496 OFF

A few short videos showing A & B tests ON/OFF of a new and improved EQ frequency response that I made a few nights ago. Behreinger ECM8000 is placed just behind the listening position sofa a few inches above seated position. Spectrumlab is recording the in-room frequency response mostly from the deep LFE.1 track. Sub bass extension Eltax A-12R was in mute mode while JBL 4645 played the LFE.1 track only and three-screen modified JBL control 5, split-surrounds where placed in mute mode.

Star Trek IV spectrumlab FBQ2496 ON

The new EQ is still pending testing at realistic levels while noting barograph display on Alesis RA300 SPL db level and frequency response on spectrumlab. One thing I don’t want is clipping and I might tailor each film to fit within the size of image VS room.

The sub bass extension is next on the testing grounds to stretch it further than before. One thing I don’t have is barograph display on the Eltax A-12R so I’d have to use instincts and common sense. I really dislike active subs no barograph display no clipping LED, that’s just not on.

I do have the LED barograph display on the Behringer FBQ2496 for input monitoring of channel A LFE.1 track channel B sub bass extension LCRS.

Anyway note the frequency response with OFF and then ON the response is much flatter with less peaks in the 30Hz to 40Hz range. The video is bit smeary I apologize for the poor digital quality.

I must say this diy JBL 4645 has been very dependable over the 11 years and I’m only just starting to explore it further.
 

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Discussion Starter #10 (Edited)
This is the frequency response I was aiming for several nights ago, this Tuesday I think? I played sine wave tones starting at 20Hz and worked my way though each one, one step at time, while adjusting the parameters of Q setting and level cut while monitoring the SPL db at 70db and aiming within ±2db tolerance level.

Some portions of the frequencies didn’t require any EQ adjustment once I got near to 50Hz to 60Hz it was relatively cool within ±2db.

Once I reached 120Hz which is rough cut-off point for the LFE.1 track discrete, I went back and did quick few frequency sweeps to see what was missing or what needed further attention. I applied a few filters on some small peaks went back to sine waves and went though each one again while looking at the Realistic SPL db metre.

I’ve only gotten around to trying the new settings this morning at soft listening levels during the later morning I’ll see where she can and can’t go but it felt good at 85dbc and smoother as well for this room.

Is there anything I can do with the frequency response below 20Hz I mean it’s a bit large and I need to reduce it and since the FBQ246 doesn’t function below 20Hz and I’ve tried few Q and cuts at 20Hz to lower it and its not going to work with what I want.

Need a filter guys or another type of EQ or filter that operates below 20Hz is there any other Behringer product that has function or filter sub sonic below 20Hz that can custom tailored for the user?
 

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