Beginners Impeadance -port tuning Help!!

[AudioFanMan]

I know there are a ton of threads on this is leading me to get a little confused, so please forgive me for something Im probably making more difficult on myself....

I have been listening to my Elsinore build for about 3 weeks, Daily blown away with how music sounds

I left my port length a tad long (1/4") figuring its easier to take material off...
In the almost 3 months the build took there was a bit of down time.
Things like weather and Uncle Fundsarelow coming in and out of town, I read as much as I could on what would be coming my way. I downloaded ARTA and REW, and have in my possession a UMM-6 calibrated mic (still unopened and in the box).

SO, Its time to measure the speakers Impedance, and looking at everything I can is confusing the poop out of me. My memory is playing tricks.. I thought I could open the software (Don't remember which one), load the calibration file for my Mic, hook up my android to the amp (using blu-tooth) and run an app that does a sweep tone while recording in again I cant remember which software, but than look for the hump...

Now trying to pick up where my memory fails, search all over again and nothing looks familiar...

One search result this site returned has a calculator asking for volume , which I dont believe I need. I believe this is overkill...
Speaker Calculations

Another thread is so old, 95% of the images are no longer working.
need some help with ARTA/LIMP - diyAudio

Anyway, with all of the long winded stuff above said, what is the simplest way to measure and graph my speakers impedance ?


Glenn

 

[Dave R]

Here's a link to a guide on how to measure impedance using Limp/ARTA.

Easy ZMA and T/S Parameters Using The LIMP Module in ARTA - An Illustrated Guide -

Techtalk Speaker Building, Audio, Video Discussion Forum

 

[AudioFanMan]

Here's a link to a guide on how to measure impedance using Limp/ARTA.

Easy ZMA and T/S Parameters Using The LIMP Module in ARTA - An Illustrated Guide -

Techtalk Speaker Building, Audio, Video Discussion Forum

Dave, Thank you...

BUT lol..

The Elsinore's are built and standing.
X-over is mounted on the back of the speakers. The cross overs have a sexy plexi glass cover... Speaker and Xover probably weigh 125 lbs each. I will not ever lay them on there backs and can not add any weights to the 4 woofers...

Is there a method without adding weights ?



Now Im thinking I asked the wrong question to begin with...

As I understand it, the impedance graph will show a saddle between to high spots, and again as I understand it, that spot in the middle of the humps or saddle is the tuning frequency of the enclosure...


I have seen it on these forums a ton of times, just dont know how to make my own.



So, to adjust port length, one would need to determine what the tuning frequency of the box is and go from there (increase or decrease port length)

 

[Dave R]

The added mass method that you are referring to is used to determine T/S parameters for the woofer. This is typically done well before the enclosure or vent is designed.

You can make an impedance measurement of a complete speaker -- mounted in box, with crossover hooked up.

Just disconnect the speaker from the amplifier before measuring.

The impedance measurement will show the two peaks which are characteristic of a vented box.