How to test frequency

[CECAA850]

Frequency response is output.  Frequency response is determined by filters and the subs output capabilities.

[TwoCables]

Frequency response is output.  Frequency response is determined by filters and the subs output capabilities.

 

Thank you. I just like to keep things simple and easy to understand though.

[Paducah Home Theater]

i agree about the filter, but if we're going to talk about 8 hz or below, another thing to consider is that most class D amps have a roll-off of at least 6 db/octave below 20 hz, which is a byproduct of crap design and will be there regardless of any filter that was done on purpose.  Also feeding it a continuous sine wave that low will cause the protection circuit to pull back greatly very quickly, it may be ok at first but after 1-2 seconds output the amp will fall off severely.  A normal amp down that low will only output a fraction of what you'd expect at 1 kHz when feeding it a since wave with a single digit frequency, even without a filter.  Gotta go with something like a SpeakerPower amp if you want super strong long term output down that low or lower.  

Edited June 29, 2016 by MetropolisLakeOutfitters

[dtr20]

Ok so I'm back to my original question. How do I check how low my subwoofer goes. I keep reading on how you advanced subwoofer guys are getting into the teens hz when you are done building your custom subs. Are you just assuming that is the frequency you are outputting based on the subwoofer calculator that you guys use, or are you confirming your actual frequency output?

[Paducah Home Theater]

Ok so I'm back to my original question. How do I check how low my subwoofer goes. I keep reading on how you advanced subwoofer guys are getting into the teens hz when you are done building your custom subs. Are you just assuming that is the frequency you are outputting based on the subwoofer calculator that you guys use, or are you confirming your actual frequency output?

 

Post 24.  Buy that microphone, do a sweep in REW, get a graph like I posted.  If you truly want to test only your sub and not your room, you'll have to take it outside, but that's another conversation.  

Edited June 29, 2016 by MetropolisLakeOutfitters

[RoboKlipsch]

I was lucky enough to have a forum member come over and show me a basic measurement and response curve.

 

You need a good quality measuring device.  In a thread over in home theater, I started one asking what device to use.  If I had seen your thread I would have just asked in here as it's basically a similar question.

 

When you are into good sound but not necessarily a techie about it, the hestitation comes from how far you want to go with this stuff, how much time and money.

For under $100, you can get a UMIK-1, as suggested in the other thread, or Omnimic, which was shown to me and was terrific (both are known to be very good).

 

You can use your cell phone or a cheap meter, but Chris A made the point that where you really want to measure (at the low end), it doesn't do so well.

 

So, do you take the plunge and spend $100 bucks to be able to measure your room?  I would say yes, if you really want to know, or if you have the ability to move the sub around or your listening position.  Because then, you are able to affect the response a great deal that way.  Otherwise, you are just curious about what it really does...in that case I might not bother to measure.  

[dtr20]

Ok so I'm back to my original question. How do I check how low my subwoofer goes. I keep reading on how you advanced subwoofer guys are getting into the teens hz when you are done building your custom subs. Are you just assuming that is the frequency you are outputting based on the subwoofer calculator that you guys use, or are you confirming your actual frequency output?

Post 24. Buy that microphone, do a sweep in REW, get a graph like I posted. If you truly want to test only your sub and not your room, you'll have to take it outside, but that's another conversation.

I checked out that site and they only have discounted mics for sale right now. Should I buy a discounted one? If so, which one?

http://cross-spectrum.com/measurement/calibrated_umik.html

[Paducah Home Theater]

I checked out that site and they only have discounted mics for sale right now. Should I buy a discounted one? If so, which one?

http://cross-spectrum.com/measurement/calibrated_umik.html

 

 

If you can get one that is an open box return that has been checked, that's probably a great deal.  I wouldn't touch any that has an admittedly weird response.  The normal UMIK's from MiniDSP will work fine as well, might take longer for shipping plus Cross Spectrum supposedly calibrates them better and lower.  

Edited June 29, 2016 by MetropolisLakeOutfitters

[JohnA]

I don't know the size of my living room off hand (I'll check later). I have hardwood floors, 8 ft ceilings, sheetrock walls. My system is all put together, I just figured there was a way to test the frequencies. I'm not aiming for a particular frequency goal, just wanted to know what it was. I tried using REW with not much luck. I would play frequencies labeled 28hz (for example), and the sounds came out of my klf30s and not my subs (klf30s only go down to 36hz). Not sure if this problem is the program, my laptop, my receiver, or all of the above.

 

You need a signal source, look in the smart phone app store, and a Rat Shack sound meter.  Look up the calibration tables on the web for the meter.  Buy/make a cable to connect your phone to your Pre-pro/Receiver and test away! 

[Paducah Home Theater]

By the time you get a radio shack meter, you could have a usb microphone and do much more with it.

[Paducah Home Theater]

I tried using REW with not much luck. I would play frequencies labeled 28hz (for example), and the sounds came out of my klf30s and not my subs (klf30s only go down to 36hz). Not sure if this problem is the program, my laptop, my receiver, or all of the above.

 

Probably mentioned elsewhere but if you set your speakers to "large" then send the signal to your receiver, this will happen.  If testing nothing but low extension on the subs, you can just bypass the receiver altogether.  Eventually you need to work on the crossover point though.  

[mustang guy]

 

Frequency response is output.  Frequency response is determined by filters and the subs output capabilities.

 

Thank you. I just like to keep things simple and easy to understand though.

 

I hear ya and I completely agree 100%. My absolute favorite forum is ELI5 on Reddit. If you haven't been there, you should check it out. 

 

ELI5 stands for "Explain Like I'm 5".   

 

Here is a link to that forum:  https://www.reddit.com/r/explainlikeimfive/ Everybody in the world doesn't want to be an expert to understand stuff. They don't want to be jibbering idiots either. Enter ELI5.  

[derrickdj1]

Ok so I'm back to my original question. How do I check how low my subwoofer goes. I keep reading on how you advanced subwoofer guys are getting into the teens hz when you are done building your custom subs. Are you just assuming that is the frequency you are outputting based on the subwoofer calculator that you guys use, or are you confirming your actual frequency output?

 

We confirm our output and FR at the main seating spot using REW or Omnimic.  A simple test to see what you are feeling is the Vibsensor app which is free and can be put on you phone.  Who cares what your output is, we all really care about what we feel, lol.

Edited June 29, 2016 by derrickdj1

[dtr20]

Fyi, I was asked this awhile ago, my room is 29' long by 13' wide