Gain/Volume Control for Passive Sub - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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
Reply
 
Thread Tools Search this Thread
Old 4th January 2015, 08:14 PM   #1
diyAudio Member
 
Join Date: Jul 2012
Default Gain/Volume Control for Passive Sub

I was previously using a NHT X2 which would do high pass, low pass, volume and phase and a ATI 1502 to power my James LP4000 passive sub. I'm currently using an Oppo 105 as both my source and preamp.

However, I've recently picked up a SVS AS-EQ1 and wanted that to replace the NHT to do phase corrections and EQ. I also have another sub in the chain which I intend to use with the SVS EQ, an Outlaw LFM-1 Plus which does have a gain control on it. To my knowledge, the SVS does not level match the subwoofers for you and you'll have to do this myself. However, I wish to take the NHT out of the chain because it's really useless now except for its volume control and it just adds an extra layer of complication.

My first inclination was to try to run the SVS EQ -> Amp -> James Sub and try to volume control it with the Oppo. However, the Oppo's output signal was inadequate in bringing the James sub to level match the James subs to the mains.

Is there a simple gain control out there to place before the amp that wouldn't be lossy?
  Reply With Quote
Old 4th January 2015, 11:18 PM   #2
tb46 is offline tb46  United States
diyAudio Member
 
Join Date: Jan 2006
Location: Texas
Hi aboroth00,

Have you tried SVS's chat or their Merlin matching tool?

High Performance - Subwoofers - Home Theater - SVS

Regards,
__________________
Oliver
  Reply With Quote
Old 5th January 2015, 04:50 AM   #3
rigtec is offline rigtec  United States
diyAudio Member
 
rigtec's Avatar
 
Join Date: Feb 2012
Location: Bergenfield NJ
Quote:
Originally Posted by aboroth00 View Post

"...Is there a simple gain control out there to place before the amp that wouldn't be lossy?"
Hi aboroth00,

I'm certainly not trying to change your specific objective in your quest, but I found myself in a similar situation a couple of years ago when I just needed a processor for my car's specialized subwoofer system. The audio system was stock; just needed some 'REAL BASS' if you know what I mean, and there was no room (or intention) for me to cut-out holes in my dash for an equalizer, cross-over, or anything else that people were recommending that I use. That's when I was introduced to the "miniDSP".

They can be used for a bunch of applications, but mine just happened to be 'Subwoofer specific', and needed to be 12V adaptable, and it was! I like it for a lot of reasons, but one is that the software controls are in my laptop (Not internet based). I control my subs 'in real time', while I'm listening so I can 'correct' as needed. The one I have has 2 analog in's and 4 analog out's so I take a signal off of my head unit from the front speakers (don't have any RCA outs). Then it goes through the processor/filter and that signal is fed to the sub amps.

When I need to EQ I plug my laptop into the USB port, click the sync button, make my adjustments to the low freq audio signal e.g., PEQ (more than 12 band capable, and I choose just what freq (in hz) each parametric band will be), X-over (you choose slope, 6, 12, 24, 48, LR, BW...). You can also create stereo High & Low pass filters if you need them. I snapped a couple of screen shots of mine just now; it's not really in operation or connected to my truck's system, just wanted you to see a few of the controls.

The best part was the price. I paid about $127 for the "miniDSP-in-a-box" (Hardware, S&H free) and then paid $10 dollars for the firmware (one time payment 'Download'). Updates are free! This first shot (below) are your gains!

Click the image to open in full size.


Below is a look at the 6 band parametric eq w/ freq centered at: 28, 34, 41, 50, 64 and 80... each band is fully configurable e.g., center freq, Q (bandwidth, .5 octv to several octv), peak, shelf, amount of gain in db... PS: There are also 6 bands PEQ on all four channels at the exit of this processor .
Click the image to open in full size. Click the image to open in full size.

And below, your X-overs as described above; you'll have quite a bit of power over your sound here as all parameters are under your control.

Click the image to open in full size. Click the image to open in full size.

And all that... in this (HxWxD) 75mm x 75mm x 30mm obscured lil' box!

Click the image to open in full size.

Here's a link to the "miniDSP" website, hope this can help!

MiniDSP 2x4 | MiniDSP

...and the miniDSP operating manual pdf in my post!

http://www.minidsp.com/images/docume...02x4%20Box.pdf

PS: I really liked the "SVS" sub that @tb46 posted; quite impressed!

Cheers!
__________________
"To overcome the "laws' of physics", you must first, obey them. Then, learn to properly exploit them, but... at a "higher level" G.S.(rigtec)

Last edited by rigtec; 5th January 2015 at 04:56 AM.
  Reply With Quote
Old 5th January 2015, 05:03 AM   #4
diyAudio Member
 
Join Date: Jul 2012
Thanks for all the advice guys. I am familiar with the minidsp and I have the UMIK-1 myself to use with REW. I was attracted to the SVS not because of its PEQ, but it's ability to smooth response across multiple LP's and tame ringing with its unique algorithms. I sort of prematurely bought it before actually measuring my setup in my new space. The crossover is being handled by my Oppo 105 which serves as my source and pre/pro.

I ended up deciding that the SVS wasn't worth the trouble especially after some positioning, I ended up with a relatively flat response. There's the hump at ~50-60hz which could use some taming, but I decided for now that it wasn't worth the trouble to add more processing to the signal chain.

My setup is currently located in the living room and it's an open floor plan so it's pretty hard to pressurize the entire space. I'm working with upwards of 600sq ft with an outlet to an upstairs hallway. I might try plugging the port of the Outlaw to get more useful extension lower. Additional thoughts or suggestions?
Attached Images
File Type: jpg fr.jpg (46.8 KB, 13 views)
File Type: jpg waterfall.jpg (84.1 KB, 13 views)
  Reply With Quote
Old 5th January 2015, 05:14 AM   #5
diyAudio Member
 
Join Date: Jul 2012
Thanks for all the advice guys. I am familiar with the minidsp and I have the UMIK-1 myself to use with REW. I was attracted to the SVS not because of its PEQ, but it's ability to smooth response across multiple LP's and tame ringing with its unique algorithms. I sort of prematurely bought it before actually measuring my setup in my new space. The crossover is being handled by my Oppo 105 which serves as my source and pre/pro.

I ended up deciding that the SVS wasn't worth the trouble especially after some positioning, I ended up with a relatively flat response. There's the hump at ~50-60hz which could use some taming, but I decided for now that it wasn't worth the trouble to add more processing to the signal chain.

My setup is currently located in the living room and it's an open floor plan so it's pretty hard to pressurize the entire space. I'm working with upwards of 600sq ft with an outlet to an upstairs hallway. I might try plugging the port of the Outlaw to get more useful extension lower. Additional thoughts or suggestions?
Attached Images
File Type: jpg fr.jpg (46.8 KB, 13 views)
File Type: jpg waterfall.jpg (84.1 KB, 9 views)
  Reply With Quote
Old 5th January 2015, 06:03 AM   #6
rigtec is offline rigtec  United States
diyAudio Member
 
rigtec's Avatar
 
Join Date: Feb 2012
Location: Bergenfield NJ
Totally cool Aboroth, glad you're getting it straightened it out!

rigtec, Rgds
__________________
"To overcome the "laws' of physics", you must first, obey them. Then, learn to properly exploit them, but... at a "higher level" G.S.(rigtec)
  Reply With Quote

Reply


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
Yet another passive volume control zatra Analog Line Level 2 13th November 2014 06:11 PM
Passive Balanced Volume Control Questions SilverStrings Analog Line Level 9 5th November 2011 08:53 PM
Remote control Passive Volume Control with Display ua100k Swap Meet 2 31st May 2011 03:01 PM
6c45 and passive volume control? AudioGeek Tubes / Valves 0 16th January 2005 10:05 PM
Gain and volume control Hybrid fourdoor Chip Amps 17 24th September 2003 10:44 PM


New To Site? Need Help?

All times are GMT. The time now is 11:06 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2