Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Impedance peak (worry or not?)
Impedance peak (worry or not?)
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 26th October 2007, 12:21 PM   #1
arc2v is offline arc2v  United States
diyAudio Member
Join Date: May 2007
Default Impedance peak (worry or not?)

I don't have the plot with me, but last night I did some detailed measurements on my OB center channel loudspeaker.

After some tweaking and fixing some mis-wiring, I got everythind sounding great.

The speaker is a 3 way design, crossed at 500 Hz (2nd order) and 3kHz (3rd order).

The ideal impedance plot is below.

the measured response of the speaker is very close to that with one exception:

There is a big peak (over 32 Ohms, which was the scale limit I was looking at) at 3-5 kHz. The ideal plot shows a smaller peak in that area.

Two questions:
1) Anything to worry about? Will it restrict dynamics in introduce any type of distortion? So far it sounds great and the amp (Outlaw) seems to handle it fine.

2)If it is a problem, what is causing it and how should I fix it? Zoebel?

Attached Images
File Type: gif adht_3way_proto_z.gif (16.8 KB, 124 views)
  Reply With Quote
Old 26th October 2007, 10:03 PM   #2
Svante is offline Svante  Sweden
diyAudio Member
Svante's Avatar
Join Date: Feb 2004
Location: Stockholm
If you drive it with a normal amplifier with reasonably short cables; don't worry. The only little concern I could have is the dip at 800 Hz, where the impedance is close to 3 ohms. You should have an amplifier that can take 4 ohms nominally in order to handle that.

You don't get distortion from a frequency dependent impedance unless the impedance is too low for the amplifier. You might get an effect on the frequency response, though, but that is typically small and depends on the output impedance of the amplifier and the cable resistance.

If the amplifier has an output impedance of 0.1 ohms, and the cable has a resistance of 0.1 ohms there will be different attenuation depending on the varying impedance.

At 25 Hz, the impedance is 15 ohms. This leads to an attenuation of 20*log(15/(15+0.1+0.1))=0.12 dB

At 800 Hz the impedance is 3 ohms, so the attenuation is 20*log(3/(3+0.1+0.1))=0.56 dB.

The difference is 0.44 dB. This means that the frequency response will whiggle by 0.44 dB due to the impedance variation. It is audible, but hardly worth bothering about.
Simulate loudspeakers: Basta!
Simulate the baffle step: The Edge
  Reply With Quote


Impedance peak (worry or not?)Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
200V peak to peak @25MHz ketan Parts 1 8th June 2008 03:21 AM
Buying worry Dr_EM Everything Else 2 8th October 2007 01:40 PM
Pre Outs and peak-to-peak ? CheekyMonkeyVZi Car Audio 7 12th December 2006 08:30 AM
BOZ voltages, worry or not? bays_9a5tt Pass Labs 2 7th September 2005 10:03 AM

New To Site? Need Help?

All times are GMT. The time now is 04:12 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio