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Quote:
Originally Posted by gperkins1973 /forum/post/16946645


Hi guys,


I am in the UK and here is my first graph with both speakers and sub on.


I have the PB13 running in 15hz tune mode.


Be good to hear what you think of it.


cheers


Graham

Isn't REW great?!


It looks pretty good at first glance but here are a couple thoughts. You should zoom in on the y axis a bit and out on the x a bit. The SPL axis in the graph posted is showing from -35dB to around 140dB which makes it hard to tell what's really going on. The x axis is only showing 2hz to 63hz which doesn't show what's going on with the crossover region. To zoom in/out on the y-axis use the magnifying glass +/- at the upper left of the graph, for the x-axis the magnifying glasses are at the bottom right. Is there any smoothing in the graph posted? It's hard to tell with the SPL range so wide. You may want to cut off anything below around 8hz or so also, unless you've got an uber-expensive mic it won't be accurate below that anyways (and likely isn't accurate down to there either).


Try tightening up the SPL to show about a 30dB range (say 60dB to 90dB or so) and broaden the frequency to show up to around 200hz and post again
 

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Quote:
Originally Posted by lennon_68 /forum/post/16947298


Isn't REW great?!


It looks pretty good at first glance but here are a couple thoughts. You should zoom in on the y axis a bit and out on the x a bit. The SPL axis in the graph posted is showing from -35dB to around 140dB which makes it hard to tell what's really going on. The x axis is only showing 2hz to 63hz which doesn't show what's going on with the crossover region. To zoom in/out on the y-axis use the magnifying glass +/- at the upper left of the graph, for the x-axis the magnifying glasses are at the bottom right. Is there any smoothing in the graph posted? It's hard to tell with the SPL range so wide. You may want to cut off anything below around 8hz or so also, unless you've got an uber-expensive mic it won't be accurate below that anyways (and likely isn't accurate down to there either).


Try tightening up the SPL to show about a 30dB range (say 60dB to 90dB or so) and broaden the frequency to show up to around 200hz and post again


Seems to me the problem is the same as most of the other graphs presented here. The baseline is too low. In this case, 85db. That is why he is showing relatively good response all the way down to 2 Hz!!!


I just don't understand why people are not running these graphs at 105 db minimum. Then you would see what happens with the 15 Hz tune under 15 Hz. Graphs of the PB-13 should be run at 105, 110, and 115 db. Then you can see the effects of power compression etc.
 

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Quote:
Originally Posted by spyboy /forum/post/16948274


Seems to me the problem is the same as most of the other graphs presented here. The baseline is too low. In this case, 85db. That is why he is showing relatively good response all the way down to 2 Hz!!!


I just don't understand why people are not running these graphs at 105 db minimum. Then you would see what happens with the 15 Hz tune under 15 Hz. Graphs of the PB-13 should be run at 105, 110, and 115 db. Then you can see the effects of power compression etc.

Agreed. I wouldn't exactly call it "good response" though, 8hz is about -30dB compared to the high point on the graph right at tuning (which is a +15dB hump in the response)... Either way you can't trust anything below 10hz so you might as well cut it off. Also it depends on why you're graphing the response, if you're EQ'ing you'd want to focus on the FR at the levels you generally listen, if you're trying to show off though you'd want to do higher level sweeps like you suggested.
 

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Quote:
Originally Posted by lennon_68 /forum/post/16948428


Agreed. I wouldn't exactly call it "good response" though, 8hz is about -30dB compared to the high point on the graph right at tuning (which is a +15dB hump in the response)... Either way you can't trust anything below 10hz so you might as well cut it off. Also it depends on why you're graphing the response, if you're EQ'ing you'd want to focus on the FR at the levels you generally listen, if you're trying to show off though you'd want to do higher level sweeps like you suggested.

I said what I said because too many people post response graphs run at 78 db to show that their $2,000 new sub is good to below 10 Hz.


As far as "showing off", the graphs by Ilkka and other respected sub testers test at 5 db increments to the highest the sub can do justice to to determine the output limits at various frequencies.


The 110 and 115 db sweeps separate the big dogs from the rest.


Of course there are other reasons to run sweeps.
 

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Quote:
Originally Posted by spyboy /forum/post/16948274


Seems to me the problem is the same as most of the other graphs presented here. The baseline is too low. In this case, 85db. That is why he is showing relatively good response all the way down to 2 Hz!!!


I just don't understand why people are not running these graphs at 105 db minimum. Then you would see what happens with the 15 Hz tune under 15 Hz. Graphs of the PB-13 should be run at 105, 110, and 115 db. Then you can see the effects of power compression etc.

your welcome to lead by example.....


Sean
 
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