Questions on xover and preamps. - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

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 31st March 2011, 10:13 AM   #1
diyAudio Member
Join Date: Nov 2008
Default Questions on xover and preamps.

I have been into home and car audio for 15 years, and more recently electronics and microcontrollers. I have a 1990 Corvette that I want to install a very high quality sound system, but I would like to design and build most of the electronics myself (xovers, amps, ect..).

I would like to build a preamp to take my signal and boost it so I don't have to turn the gains on my amplifiers up all the way.

Also, while the design is not nailed down yet, I think I want a 4-way system with a subwoofer in the rear, and tweeters, mid ranges and mid woofers in the front.

My questions are:
1. Is it feasible for me to build an active crossover with very low distortion? Circuits on the web show it basically just requires an op amp and about 4 resistors and two capacitors for a low or high pass filter.

2. Should I preamp the signal before splitting frequencies, split the signal first and then boost each one, or both?

3. More questions to come as these are answered and I learn more about this stuff.
  Reply With Quote
Old 31st March 2011, 12:22 PM   #2
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
Mooly's Avatar
Join Date: Sep 2007
It's thought of as bad practice to amplify a signal and then have to attenuate it, mainly because of the very very small noise penalty.

1. Depends on your construction abilities... and yes, basically an opamp and a few passives. Getting the values of the filter correct and realising there are many different types of filter response is a whole different thing. Look up Butterworth, Linkwitz-Riley and Chebyshev filters.

2. It's good practice as a general rule to buffer the signal... so the input characteristics of the design are known. The signal that is split and fed off to different filters should be buffered too because filters need to be fed from as low an impedance source as possible. If they are not then the source impedance driving the filter affects the actual response of the filter and causes it to deviate from the ideal.

Noise from extra opamps is a non issue in practice, just keep the impedances at sensible values.
  Reply With Quote


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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
preamps smokinone Solid State 0 27th December 2010 05:17 PM
Preamps? cleatus Everything Else 9 11th October 2006 03:48 AM
D.Self preamps hihopes Solid State 9 3rd November 2005 07:26 PM
More xover questions mr_push_pull Multi-Way 4 21st September 2004 06:12 AM
Some xover questions from neophyte plasmodium Multi-Way 2 19th November 2002 01:11 PM

New To Site? Need Help?

All times are GMT. The time now is 09:40 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2