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RCF ESW1018 vs EV T18 (FR and Impedance curve)
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Botabaixo View Drop Down
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    Posted: 30 August 2020 at 10:31pm
Hi.

This weekend I carried out a comparison between the T18 and the ESW1018.
Knowing that they are boxes with identical size, 
I wanted to know the main differences in the frequency response and the impedance curve.
The driver used was the same in both boxes (RCF L18S800).
The esw1018 box is original the T18 is a copy.

Here are the results:




The frequency response was made with the box on the floor.




Edited by Botabaixo - 30 August 2020 at 10:33pm
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Conanski View Drop Down
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Points: 2401 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2020 at 11:26pm
Unfortunately I think your comparison is useless, if you measured indoors in the space shown in the pic then you measured the room more than the speakers and that is why the response is nearly identical. Get these outdoors well away from structures and try again and I bet the results will be quite different.

For reference the factory response for the t18 is below..




Edited by Conanski - 30 August 2020 at 11:29pm
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Botabaixo View Drop Down
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Points: 18 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Botabaixo Quote  Post ReplyReply Direct Link To This Post Posted: 31 August 2020 at 12:27am
I don´t think that is useless, if I gona use it indoors....
I know the graphs from both boxes, they are very identical.

The ESW1018 and T18 Frequency response:

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Jo bg View Drop Down
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Originally posted by Botabaixo Botabaixo wrote:

I don´t think that is useless, if I gona use it indoors....

It will still be useless, unless you put it in a venue same size as the one you measured in AND put subs in same postion. 
even changing one meter postion will change response a lot, immagina a different shape and size room eith different absorption caracteristics.

The only thing you can gather from  this,  is diffence between cabs, as you are measuring them close room influence should be similar.
But the frequency repsonse has no absolute value, even different ceiling height will make a difference.
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Botabaixo View Drop Down
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Originally posted by Jo bg Jo bg wrote:

Originally posted by Botabaixo Botabaixo wrote:

I don´t think that is useless, if I gona use it indoors....

1.It will still be useless, unless you put it in a venue same size as the one you measured in AND put subs in same postion. 
even changing one meter postion will change response a lot, immagina a different shape and size room eith different absorption caracteristics.

The only thing you can gather from  this,  is diffence between cabs, as you are measuring them close room influence should be similar.
2.But the frequency repsonse has no absolute value, even different ceiling height will make a difference.



1. The measurements were taken with the speakers in exactly the same position.
2. If the frequency of response is useless, how do you assess which speaker is best for a given circumstance? By ear?
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Points: 1568 		Post Options Post Options   Thanks (0) Thanks(0)   Quote mobiele eenheid Quote  Post ReplyReply Direct Link To This Post Posted: 31 August 2020 at 1:51pm
Useless is such a big word that seldomly fits every perspective, it's almost useless to use it.

If your software has the ability set the gate before the first reflection. Say the first (closest) wall is 5 meters away, the first reflection (apart from the ground) will arrive in 30 milliseconds. In a large space the ceiling is often the first reflection. If you set the gate below this 30 milliseconds, it will be excluded from the measurement.
However a shorter gate time will limit how low you can measure accurately. The lower you want to measure the longer the gate time needs to be, so you might have to make a compromise between reflections included and how low you want to accurately measure.
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bass*en*mass View Drop Down
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ignoring the bump and the spike i guess both are tuned to about 50hz and are not useable much above 100hz.. - bet they are loud in their, narrow, passband, both dont look great imho tbh. :(
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Conanski View Drop Down
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Points: 2401 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 31 August 2020 at 11:08pm
Originally posted by Botabaixo Botabaixo wrote:

I know the graphs from both boxes, they are very identical.

Wow they are pretty much identical, I didn't know that but it explains your results. 

Still, if you were to EQ the response to look sensible in that location you would likely try to fix at least a couple response anomalies(the dips at 58hz and 116hz) that the speakers aren't responsible for, so for that reason the measurements aren't of much value. 
P.S. The fact that those 2 dips are exactly multiples of one another strongly suggests a boundary reflection cancellation, and no amount of EQ would have any effect on them.


Edited by Conanski - 31 August 2020 at 11:16pm
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bob4 View Drop Down
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Points: 1783 		Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 01 September 2020 at 7:01am
Useless is a strong, but appropriate word in this case. The only thing you can see from the graph is the cancellation from the back wall, which is abit over 3 m away, and results in cancellation at about 57 and 114 Hz. 

It is common and agreed practice that subwoofers need to be measured outdoors. Whining and denial doesn't change the fact. Listen to the advice, there are very experienced and smart people on this forum (i don't count myself in that group). They answer for the fun of it to educate newcomers. 

Listen & Learn

Edit: while the measurement result is pretty much useless, i don't think your effort was useless. You practiced using the software, you got some data, now it is just a matter of learning from it. If your data is useless, you have to simply get new data. 


Edited by bob4 - 01 September 2020 at 7:06am
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sushi View Drop Down
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Points: 85 		Post Options Post Options   Thanks (0) Thanks(0)   Quote sushi Quote  Post ReplyReply Direct Link To This Post Posted: 04 August 2021 at 7:05pm
Good effort in test and research always pays. You always learn something, maybe it's not that information you were looking for but it's still a good thing.
The most important and decisive thing determining a speaker system's response is the environment around the system itself. Have you ever tested a loudspeaker indoor and felt sound pressure, but later found the volume wasn't enough outdoor? Well, it's all about sound reflection. Shortest reflections can alterate real sound perception: waves from the speaker that bounce on the cieling or on nearby walls and get to your hear a few milliseconds after the main soundwave coming from the box. They change the actual speaker response, ehanance or cancel some frequencies. If we can hear it, microphones will do as well. So, if you put those two boxes in half space (a field, or an empty parking lot where the floor is the only significant boundary) you surely going to get some changes in your graph, and that would be the common way to get sub speakers tested.
Anyway, the cabs have the same driver but different loading, i bet some differences have been totally flatten by the overall room's response which is the one you measured this time.
It would be interesting to see outdoor measurement graphs. As an ESW owner, i'm going to get my 4 measured soon. I loaded them with the 801.
Cheers!


Edited by sushi - 04 August 2021 at 7:14pm
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kedwardsleisure View Drop Down
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Quote i guess both are tuned to about 50hz and are not useable much above 100hz.

In this neck of the woods the ESW1018 is known as a one-note bass box.
Kevin

North Staffordshire
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