Hi,
i'm new to this forum 🙂
I'm in the progress of building my 1s diy passive speaker,
and have this strange problem.
It sounds like there's big loss in 150Hz, 300Hz, 600Hz and so...
Tried to play sine wave tone on one channel only and it's evident those notes have smaller volume than the rest.
The same issue also appear on the other channel.
I guess it's a box issue?
What can be the cause?
Any inputs are much appreciated.
Thanks!
i'm new to this forum 🙂
I'm in the progress of building my 1s diy passive speaker,
and have this strange problem.
It sounds like there's big loss in 150Hz, 300Hz, 600Hz and so...
Tried to play sine wave tone on one channel only and it's evident those notes have smaller volume than the rest.
The same issue also appear on the other channel.
I guess it's a box issue?
What can be the cause?
Any inputs are much appreciated.
Thanks!
Hi,
sorry i don't have any pics yet.
It's pretty standard two way bookshelf.
Width is 22cm, height is 38cm, and depth is around 32cm.
Woofer is sb acoustic 6" low passed at 3K 12db.
sorry i don't have any pics yet.
It's pretty standard two way bookshelf.
Width is 22cm, height is 38cm, and depth is around 32cm.
Woofer is sb acoustic 6" low passed at 3K 12db.
I'm using REW.
Measuring at around 1m also shows the issue:
There's strange thing on the GD as well, correlate to the same frequency:
Listening in room (around 3m from the speaker) also reveal the same issue.
And it happens to both speaker box... even though the speakers are of course placed apart.. hmmm
Measuring at around 1m also shows the issue:
An externally hosted image should be here but it was not working when we last tested it.
There's strange thing on the GD as well, correlate to the same frequency:
An externally hosted image should be here but it was not working when we last tested it.
Listening in room (around 3m from the speaker) also reveal the same issue.
And it happens to both speaker box... even though the speakers are of course placed apart.. hmmm
Are you hearing the lack of bass or just looking at the graph? Can you hear it in the music? I have great bass in my room, but it measures sort of like yours with REW.
Yep, in room...
Moving mic closer/further or left/right seems to reproduce the same graph in that 20-200Hz region... the treble does change a lot though.
Moving mic closer/further or left/right seems to reproduce the same graph in that 20-200Hz region... the treble does change a lot though.
Somehow i think this is enclosure related, cause the problem exist in both box.
Will bracing help? The box is built using 1" mdf. Right now bracing only done from front to rear panel, but not up-down.
Or is it leaky? Does air leak create bass cancellation?
Any idea how to check?
Will bracing help? The box is built using 1" mdf. Right now bracing only done from front to rear panel, but not up-down.
Or is it leaky? Does air leak create bass cancellation?
Any idea how to check?
It looks like a possible reflection off the back wall. To show this is the cause move the speakers forward or back and the frequency of the dip should change.
Beat me to it.😀
I'd change distance to all boundaries- the Allison effect is from interactions with all of them- and remeasure. If you can find a copy of Bestplace software (from RDL) and plug in the numbers for your speaker to back wall, side wall, and floor distances, I bet you'll see exactly the same pattern of dips.
Distance from the floor to the center of the woofer. Floor type? As asked earlier that is in the the range where and early reflection is causing phasing issues.
Speaker on stands?
Distance from side walls?
Distance to ceiling?
Speaker on stands?
Distance from side walls?
Distance to ceiling?
I believe that this is floor bounce cancellation. Could be also ceiling or wall bounce or all together. All room measurements below 500Hz show reflections and room modes.
The easy way to measure the speaker is to do a nearfield measurement, at just 2-5cm from the bass cone. But then all other drivers' responses are attenuated.
You must understand that indoor speaker measurements are very difficult, almost always you are actually measuring room's reverberant field.
Room (listening spot) measurements help you to position the speakers and furniture to get best possible response! Speaker tuning is more diffcult because you must make arrangements to simulate anechoid chamber.
Please study the Help files of REW, looks like you are using it!
The easy way to measure the speaker is to do a nearfield measurement, at just 2-5cm from the bass cone. But then all other drivers' responses are attenuated.
You must understand that indoor speaker measurements are very difficult, almost always you are actually measuring room's reverberant field.
Room (listening spot) measurements help you to position the speakers and furniture to get best possible response! Speaker tuning is more diffcult because you must make arrangements to simulate anechoid chamber.
Please study the Help files of REW, looks like you are using it!
Hi,
thanks everyone for the reply.
I add some more internal bracing:
1. From top panel to center brace
2. From the front panel, left side and right side of the woofer to the back panel
The result is satisfactory now 🙂
This is the FR:
(blue is the original without additional bracing, and red is with 3 new bracings)
And this is the GD:
My small box needs a lot of bracing!
thanks everyone for the reply.
I add some more internal bracing:
1. From top panel to center brace
2. From the front panel, left side and right side of the woofer to the back panel
The result is satisfactory now 🙂
This is the FR:
(blue is the original without additional bracing, and red is with 3 new bracings)
An externally hosted image should be here but it was not working when we last tested it.
And this is the GD:
An externally hosted image should be here but it was not working when we last tested it.
My small box needs a lot of bracing!
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