Re: Harbeth 30.2 in room, real-time frequency response measurements
Quote:
Originally Posted by
Puma Cat
Actually, this IS the easiest way. Ask any good engineer.
Yeah, right.
Re: Harbeth 30.2 in room, real-time frequency response measurements
Quote:
Originally Posted by
Puma Cat
That's remarkably smooth. Almost too much so, in the bass. Top looks about right. What resolution are you using? Where is the mic?
Quote:
Originally Posted by
Puma Cat
Next, I'll see if I can smooth out some peaks and nulls and get the response above 4K up a skosh...
More later, stay tuned....
I wouldn't do that. That is a "summed" pressure response at a single pressure mic position. It gives info, but that isn't quite what your 2 ears binaural hearing system hears. Move the mic around a bit more, watch the bass holes fill and see other peaks. I would go very gently there, especially boosting to fill pressure nulls. That will affect the direct response of the speaker, which is mixed in to that "summed" response. Possibly for the worse.
Take one range at a time, bass/mid/treble. Make gentle adjustments with one only, use your 2 ears to test the results with a wide variety of familiar tracks. It's very easy to go astray here. Based on the direct native responses of the speaker, I'd leave the bass alone, maybe add a shallow broad Q dip centered around 4k and then a bit of boost >12k....depending on your age.
cheers,
AJ
Re: Harbeth 30.2 in room, real-time frequency response measurements
Stephen, Are you planning on using any type of equalizer? I assumed you were just playing with your subs crossover controls and room positioning of mains and the sub, perhaps listening position??
Re: Harbeth 30.2 in room, real-time frequency response measurements
Quote:
Originally Posted by
AJ Soundfield
That's remarkably smooth. Almost too much so, in the bass. Top looks about right. What resolution are you using? Where is the mic?
I wouldn't do that. That is a "summed" pressure response at a single pressure mic position. It gives info, but that isn't quite what your 2 ears binaural hearing system hears. Move the mic around a bit more, watch the bass holes fill and see other peaks. I would go very gently there, especially boosting to fill pressure nulls. That will affect the direct response of the speaker, which is mixed in to that "summed" response. Possibly for the worse.
Take one range at a time, bass/mid/treble. Make gentle adjustments with one only, use your 2 ears to test the results with a wide variety of familiar tracks. It's very easy to go astray here. Based on the direct
native responses of the speaker, I'd leave the bass alone, maybe add a shallow broad Q dip centered around 4k and then a bit of boost >12k....depending on your age.
cheers,
AJ
Thanks, AJ!
This was very helpful info, I will try out some of your suggestions. The mic is at one of my two primary listening positions, 7 ft 6 in. from each speaker. The speakers, per Harbeth's guidance are 2 meters apart, center to center.
As for resolution, I am using 1:3 in REW. I'll move the mic around a bit and see what happens.
Craig also suggested moving the speakers around, so I'll play with that a bit, as well. That was a good suggestion that I want to investigate just to learn what happens when I do that (we learn by doing experiments, that's the fun part! :D)
I'm not an acoustical engineer, so what is a Q-dip? I'm not sure how I would add it w/o some form of equalization. As for a boost above 12K, I have no way to affect that, either. I have an external tone control that I could try if inclined (The Delicious One from Alberto).
Thanks for the suggestions.
Re: Harbeth 30.2 in room, real-time frequency response measurements
Quote:
Originally Posted by
crwilli
Stephen, Are you planning on using any type of equalizer? I assumed you were just playing with your subs crossover controls and room positioning of mains and the sub, perhaps listening position??
Hi Craig,
No, no plans on using an equalizer. You're correct that I'm just playing with sub's controls: Gain and Crossover. The control that has the biggest effect is the Gain control.
And yes, I am just playing with the position of the mains and sub, to an extent. I'm going to take you up on your suggestion to move the mains around a bit. Right now, they are about 31" in front of the front wall (which is a half-wall, BTW) I don't have much wiggle room as my space is small...you guys would be "shocked", its not a dedicated listening room, but...it works and...it sounds really good. I'm trying do the best I can with what I have to work with. The good thing is, Harbeths work really well with both near-field and mid-field listening. ;)
Re: Harbeth 30.2 in room, real-time frequency response measurements
So, I followed up on Craig's suggestion and have been playing around with placement of the 30.2s. I turned the sub off to fine-tune the position of the mains, and I'm using a laser "tape measure" to measure the position of the mic to each speaker.
This plot is from my "#2" listening position, which is along a diagonal; there is effectively no back wall in this config, as the speakers fire down a 30' long hallway. This is how I listened to my Dyns for many years for "critical listening". The speakers are 9 1/2 feet from the mic; the speakers are ~2 meters apart per Harbeth's guidance.
This plot is double the resolution of the previous plot, with a 1:6 smoothing and is the average of both the L and R channels. Target SPL is 75 dB, so the horizontal reference line is set to that in the plot.
http://photos.imageevent.com/puma_ca...%20vs%20FR.jpg
I dunno, this seems to be lookin' pretty good....as Craig mentioned, looks like I want the sub to bring up just in the range under 80 Hz.
Re: Harbeth 30.2 in room, real-time frequency response measurements
Sorry for late response, it's been a madhouse here due to impending hurricane.
Quote:
Originally Posted by
Puma Cat
The mic is at one of my two primary listening positions, 7 ft 6 in. from each speaker. The speakers, per Harbeth's guidance are 2 meters apart, center to center. As for resolution, I am using 1:3 in REW. I'll move the mic around a bit and see what happens.
You should use at least 1/6th octave, or the psychoacoustic smoothing option, looks like you've done the former. That will help identify any peaks in bass that may need mitigation.
Quote:
Originally Posted by
Puma Cat
I'm not an acoustical engineer, so what is a Q-dip? I'm not sure how I would add it w/o some form of equalization. As for a boost above 12K, I have no way to affect that, either. I have an external tone control that I could try if inclined (The Delicious One from Alberto).
The Q is essentially the frequency width/range of your boost/cut. Since you are not using EQ, its moot.
I would not have moved speakers based on you first graph despite the too low resolution, unless there were problems with sound/bass/imaging. Moving the mic around would show how much the bass changes over small distances...and why boosting nulls/dips isn't a great idea. Judicious cuts to peaks are ok.
Quote:
Originally Posted by
Puma Cat
This plot is double the resolution of the previous plot, with a 1:6 smoothing and is the average of both the L and R channels. Target SPL is 75 dB, so the horizontal reference line is set to that in the plot.
I dunno, this seems to be lookin' pretty good....as Craig mentioned, looks like I want the sub to bring up just in the range under 80 Hz.
Try posting individual L R (1/6th), not averaged. Agree the sub may need to come up a bit. How does it sound?
