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Discussion Starter · #1 ·
I have seen a lot of images of measurements of frequency responses on this site, and was wondering what kind of equipment/software u guys are using to measure this?


Have found some programs on the internet, but these only allow me to measure for the left/right channel. But I am going to use it for HT and therefore must be able to measure all 5 channels. I use SPDIF output on my computer.


I have tried the MCACC calibration on my Pio-receiver, but it does not seem like it can show the frequency curve/SPL graphs.
 

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RoomEQWizard is freeware that will do such measurements but it is mono and you would have to test each channel independently. It will work with a RS slm or with better mics/preamps.


If your needs are simpler, look at TrueRTA.
 

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Discussion Starter · #3 ·

Quote:
Originally Posted by Kal Rubinson /forum/post/15580378


RoomEQWizard is freeware that will do such measurements but it is mono and you would have to test each channel independently. It will work with a RS slm or with better mics/preamps.


If your needs are simpler, look at TrueRTA.

Thanks for the reply! I have already looked at "RoomEQWizard" but as far as I can see, it cannot for example measure for the left surround speaker. Or the center channel for that matter. Would I have to switch connections on my amp each time for measuring each speakers?
 

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What would be wrong with using REW to measure the surround channels by sending the analog line-out to the multi-analog-inputs on the receiver?
 

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Quote:
Originally Posted by JonasHansen /forum/post/15580425


Thanks for the reply! I have already looked at "RoomEQWizard" but as far as I can see, it cannot for example measure for the left surround speaker. Or the center channel for that matter. Would I have to switch connections on my amp each time for measuring each speakers?

Yup. That's what I said. I know of no standalone systems to do all channels without reconnecting except expensive EQ setups.
 

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Quote:
Originally Posted by JonasHansen /forum/post/15580363


Have found some programs on the internet, but these only allow me to measure for the left/right channel.

Not uncommon. Measure 2 channels at a time. If you measure one channel with most software, the other channel's response is like a line at the bottom of the graph.


Quote:
I use SPDIF output on my computer.

Measuring frequency response in the digital domain is usually a strange thing to do. By default, the frequency response of a digital device is perfect below the Nyquist frequency (half the sample rate).
 

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Discussion Starter · #7 ·

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Originally Posted by arnyk /forum/post/15587814


Not uncommon. Measure 2 channels at a time. If you measure one channel with most software, the other channel's response is like a line at the bottom of the graph.





Measuring frequency response in the digital domain is usually a strange thing to do. By default, the frequency response of a digital device is perfect below the Nyquist frequency (half the sample rate).

The reason I want to measure the frequency response of my speakers, is just because I want to see how linear my system/speakers are in my room. I don't think it would make any difference if it is digital or analog?
 

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I don’t really care for sound at the moment as my cat is feeling poorly,
but here goes.


I use several devices REW and spectrumlab where I ran frequency sweep from REW sound generator I look at the colour of the paten that as a few gaps hence (room mode).


I have come up with lesser challenge as sorting this issues out can be quite costly.


Simple solution is to check for even as possible frequency response of the LCR down to its crossover cut-off-point. Let’s say 80Hz or in my case I can choose any crossover I like with the DCX2496 any crossover.


Room modes are like black holes and you can have thousands of watts or voltage and its not going to help if you have dips greater than 30 or 40db down. You have to treat the room and the silly costs some manufactures are asking is daylight robbery.


In real life there are dips and peaks and its impossible to FIX now then. The homes’ room maybe something one might want to take pride in trying to achieve flat uniform frequency response over the seating area, within few +- db.


Moving the sofa forwards after doing a quick frequency check of the LCR says a few meters from the front is good for mid bass kicks and little thumping soft sounds that will be completely lost at the back.


Trail and error for each room that is different and the challenges are tough doing it on your own moving the mic hare and there moving a speaker hare and there and it goes on and on till finally your committed to the hospital. Where you keep telling the doctor (room modes are important to solve), (here son, take this calm down and get some rest).



Remember room modes suck!


I also have TrueRTA free version number 1, I should buy the full package version as its valued tool like REW.


I could use REW (pink noise custom mode) along with Spectrumlab to give me waterfall response and I can see the hot spots that need addressing as well as gaps in the frequency response that also needs attending to.


And like I said easiest way is to relocated the sofa its far better than lugging speakers around all the time.



If you place the microphone within a short distance of the centre channel and slowly move it back after recoding a few seconds. Look at the waterfall on each 1 foot or so and it gradually starts to change.


It would take pot luck to get the best frequency response over the matching LCR fronts pot luck. The sub bass is pain in the neck and it may take many of the same sub bass placed and stacked up front or (mutual coupling).


Along with independent parametric EQ to address each sub as one might produce too much at different frequencies and so forth.


Use the rooms’ front width and stack as many as possible not for silly stupid SPL db levels but for even smooth frequency response. Not sure if this going to be the same all-around the room or just cater for the few seats in the sweet spot.


Stacking subs around the entire room may solve the issue at an extremely high cost I mean a high cost because you need independent parametric EQ to tailor the room out from…


Front side to side

From mid point in the room side to side

From rear side to side


Up and down and hmmm, maybe subs fitted in the ceiling and not forgetting the floor now how does one go about doing the floor as this isn’t easy? You could have sub flooring laid down and a few a few subs placed around the sides of the room flush fitted with metal grills protecting them.


But it doesn’t protect them from liquid spilling onto it!


Bass shakers might be an answer but from most of what I’ve read they going up in flames like The Towering Inferno!
 

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Quote:
Originally Posted by glaufman /forum/post/15585821


What would be wrong with using REW to measure the surround channels by sending the analog line-out to the multi-analog-inputs on the receiver?

Easy simple because REW only has two channel output doesn't mean a damn thing and so go for it remember to turn off or mute or disconnect cables to other speakers otherwise you'll only add the other channels' frequency response to the graph. It can take days to EQ days, good luck, your going to need it.
 
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