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Discussion Starter · #1 ·
Hello and thank you for all the great things this forum and the REW developers / tutors do. Amazing stuff!

So I am new to this program and running associated test measurements. I do have a background in audio engineering (new school audio engineering, I record and mix music for a living). When I was at school 15 years ago we studied SMAART but I never used it outside of class. I do understand a some of the theory behind impulse response measurements and the terminology behind it. What I am not used to is using this knowledge in a practical way because I have very little hands on experience with it.

I bought some new monitors for work and thought I would dive into this area again after all these years. The new speakers got me pretty excited I guess and I want my mixes to translate better faster outside the studio.

So the nitty gritty of my questions and observations. Sorry for the long post.

I have a a a pair of JBL LSR 4328P monitors. My room is pretty much untreated and typical 15X12X12.
The new JBL speakers are unquestionably better sounding than my old paradigm ones. The mid-range clarity is just night and day better plus the extended lows and highs.

I download REW, and Equalizer APO, read and read some more. Making test measurements after calibrating my soundcard and loading a generic calibration file for the Radio Shack SPL meter I have (Got a calibration mic ordered so measurements will get better I assume).

Process is

Calibrate soundcard
Load SPL meter calibration - C weighted
calibrate SPL
set the settings to correct speaker settings (full range bass limited) 50Hz cutoff 12dB/Octave.
make measurement with Pink Noise PM

Questions

1-The JBL LSR4328P response from factory claim +/- 1.5 dB from 50Hz-20kHz. They are much "brighter" than my old speakers. I love how they sound. But when I look at the response taken in REW they are very exaggerated up near 10k. Is it possible that JBL is misleading with their claims or could my room be messing up the response that bad?

2 - While running EQ APO with the filters generated by REW the sound is less then pleasing. I assume user error is the culprit and I really hope so. Maybe it's the house curve section I haven't got to yet or maybe I'm going def in the up bands(I can hear 17.5kHz) Maybe its the SPL meter.

I'm just looking for some thoughts on all this. I'll post a graph after I go back and read the image posting rules.

thanks again!

Mike
 

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Welcome to the Forum, Mike! :T


1-The JBL LSR4328P response from factory claim +/- 1.5 dB from 50Hz-20kHz. They are much "brighter" than my old speakers. I love how they sound. But when I look at the response taken in REW they are very exaggerated up near 10k. Is it possible that JBL is misleading with their claims or could my room be messing up the response that bad?
Perhaps JBL is tweaking there specs, but you’ll never be able to tell with measurements taken with a SPL meter using a generic calibration file. Regardless, you can be assured that the room will affect response.


2 - While running EQ APO with the filters generated by REW the sound is less then pleasing.
If you can’t get a reliable measurement with a SPL meter and generic calibration file (see above), you certainly don’t want to do any equalizing based what it’s telling you.

What you’re doing now is certainly a great exercise to get a feel for REW, but wait until you get your calibrated mic before you start getting worried about your speaker’s measurements and any EQ they might need.

Regards,
Wayne
 

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Discussion Starter · #3 ·
Most excellent! I'm so relieved to here it's user error! lol...

I was reading your house EQ curve articles. How does that theory relate to the response of the speakers as reported by the manufacture. Say if a speaker is rated at +/- 1.5 from 50Hz-20kHz, aside from the response from the room, it would seem to go against the house curve idea.

When I look at music mixes in a RTA the signal usually has a house curve look to it. But I would also assume speakers are like other pieces of audio gear, like microphones or sound-cards, in that I wouldn't want them to impress a change on the data other than the effect intended or aesthetic intended.

What do you think about claims of flat response from speakers? The Earthworks speakers would be a good example. Extremely flat, extended and time coherent. If house curves are normal why have a speaker that is flat?

Maybe the idea is if I am going to alter something then at least I did it and not the gear forcing me to?

anyway, I'll be back with more questions.

thanks again!
 

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Most excellent! I'm so relieved to here it's user error! lol...

I was reading your house EQ curve articles. How does that theory relate to the response of the speakers as reported by the manufacture. Say if a speaker is rated at +/- 1.5 from 50Hz-20kHz, aside from the response from the room, it would seem to go against the house curve idea.
One has nothing to do with the other. Good speakers are designed for reasonably flat response in an anechoic chamber. However, when it is placed in a room, rated response goes out the window. A house curve is a room curve, and how steep it is depends on the size of the room, listening distance from the speakers, etc.


When I look at music mixes in a RTA the signal usually has a house curve look to it.
Correct, a recording that sounds balanced looks like that when the signal is fed through a RTA. However, it will only sound right through a speaker with linear response.

Regards,
Wayne
 

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Discussion Starter · #5 ·
Thank you Wayne. That makes sense to me. Speakers are tested and calibrated in an anechoic chamber for ideal flatness so to impose as little distortion as possible at the output. When placed in a room the speakers perceived response is distorted because of the rooms dimensional related acoustic phenomena. So flat linear speakers are good, bad rooms mess them up. House curves are goal specific for a room response.

I love this site!
 
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