Port peaks


New Member
Thread Starter
Jun 5, 2017
My AV System  
Main Amp
Luxman 550
Front Speakers
Marten Miles 5
Hi all.
I'm building a two way speaker.
in order to do some tests for the box volume and port tuning , i build a test enclosure.
I'm testing different volumes and tuning frequencies.

The drive i use is Dayton Audio DS135-8.
The suggested volume for this drive is ~5 liters.

during measurement of the port i notice unwanted peaks which are very high in db SPL.
They are to low to be port resonance.
I tried 2 port diameters: 35mm and 28.

Attached is an image with the test results and enclosure description.

initially i had the port on the top
Port with a length of 53mm and diameter of 28 (this was an initial guess on the ruining frequency.

You can see there are meany peaks.
I then moved the port to the back of the box and the 220Hz beak disappear.

I change to a bigger port, diameter 35mm and a length of 60mm.
no effect on the peaks.
I also increased the box volume to 9 liter instead of 5. no effect.

Can you say what is the source for these peaks? can it be fixed?
Thank you


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