Will an amp significantly alter box volume?? - 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 10th March 2002, 12:07 AM   #1
diyAudio Member
 
Join Date: Feb 2002
Location: Chicago, IL
Post Will an amp significantly alter box volume??

I'm building a 85L traditional vented sub using the plans found on Adire Audio's web site...except, I just reailzed that my sub will be *not* be passive like their design. My amp (Adire AVA250) is in transit, so I don't know how far it will protrude into the box. I really hope that I can still proceed using Adire's design and not have the sound dramatically altered as a result of the amp. What's the consensus out there?? Thanks.

Grant
  Reply With Quote
Old 10th March 2002, 12:39 AM   #2
Wizard of Kelts
diyAudio Moderator
 
Join Date: Sep 2001
Location: Connecticut, The Nutmeg State
According to the Adire website, your amp measure 10.5" X10.5" X3.5" for a total of 386 cubic inches. That is less than a quarter of a cubic foot. Your 85 liter enclosure is about 3 cubic feet. The amp will occupy less than 8% of your internal space, a completely negligible amount.

Essentially, it makes your 85 liter enclosure a 79 liter enclosure. If you have a loudspeaker program, you can run the two volumes and see how little difference it makes.
  Reply With Quote
Old 10th March 2002, 01:33 AM   #3
diyAudio Member
 
Join Date: Feb 2002
Location: Chicago, IL
Thank you Kelticwizzard!

Grant
  Reply With Quote
Old 10th March 2002, 11:18 AM   #4
diyAudio Member
 
promitheus's Avatar
 
Join Date: Jan 2001
Location: Germany
For a vented sub I think 5-10% is acceptable. It shouldn´t change mucht he sound. Maybe a little the frequency response but no big difference.
  Reply With Quote
Old 10th March 2002, 02:47 PM   #5
Super is offline Super  United States
diyAudio Member
 
Join Date: May 2001
Location: Connecticut
Send a message via AIM to Super
You could always build a separate enclosure for your amp. Thats what I did for my AVA-250. All it took was 4 pieces of scrap wood for walls, and some spikes on the bottom to keep it elevated for even better ventilation.
__________________
Bryan
  Reply With Quote
Old 10th March 2002, 10:26 PM   #6
diyAudio Member
 
Join Date: Jan 2002
Location: Netherlands
Default Volume difference?

Grantbo,

First, your 8% difference is not that much. It depends on you hunger for detail if you want to call this negligible or not. There some parameters the will change by changing the volume.
Changing the volume will change QL (decreases). This results in an earlier roll-off for f3.
There are “unnatural” ways to compensate this QL loss.
The volume calculated in respect to a certain QL depends on the Qts of your speaker. So, if you were in designing a speaker your two anchor points are Qts and QL. Ideally you want to have a QL of 7. If you do not want to change the characteristics of the enclosure, you should stay away form QL. This leaves you no choice to change the Qts of you speaker. This can be done in many ways. Two of which are fairly simple.
1) Change the DC resistance of the speaker coil (Revc).
2) Change the mass of the cone (Mmd).

Anyway. It’s not worthwhile to change any of your speakers parameters. But if you have some spare time and you’re in the position that you can measure you’re speaker changes, it will give you a piece of profound knowledge.

Like a said, it’s for the detail freak .

Good luck in building you’re Sub.
  Reply With Quote
Old 11th March 2002, 01:38 AM   #7
diyAudio Member
 
Join Date: Feb 2002
Location: Chicago, IL
Thanks for the follow-up guys. Given the small change in volume, I will leave the dimension specs as is. *But*...would it make sense to add a little fiber filling to the box to give it a little boost in "perceived" vol.? Adire's plans do not call for filling in their 85L sub, but from what I've read, it appears to be a very popular option amongst sub builders. Will adding filling (either filling the box or lining the walls) alter the acoustic properties that Adire has
so carefully determined??

Grant
  Reply With Quote
Old 11th March 2002, 02:28 AM   #8
Super is offline Super  United States
diyAudio Member
 
Join Date: May 2001
Location: Connecticut
Send a message via AIM to Super
Filling can definitely tidy up bass and help reduce "muddle". If its a vented design, you would just want to line the inner walls. If its sealed, you should fill it loosely. Yes, adding stuffing can theoretically "increase" your volume, but it can have a diverse effect on the sound quality if over/understuffed. Your best bet is to play around with the stuffing before sealing up the box for good. I lined the innards of my sonosub with some extremely dense egg crate foam (I get it for free from a local specialty manufacturer), and despite my cuts not being perfect, my tuning frequency was within about 1/2 hz (lower!) than the desired frequency.
__________________
Bryan
  Reply With Quote
Old 11th March 2002, 05:04 AM   #9
diyAudio Member
 
Join Date: Feb 2002
Location: Chicago, IL
So, I've cut out the required box panels today, tomorrow night is set aside for routing, the AVA-250 amp and 12" Shiva driver are
on there way...but what is the recommended method/wire/cable to connect:

1. The Shiva-to-amp
2. The amp-to-receiver's RCA subwoofer out?

For #2, would a simple RCA cable with single jacks on each end
suffice, or do I need a T-type cable to connect to two amp jacks?

Grant
  Reply With Quote
Old 12th March 2002, 11:37 PM   #10
Super is offline Super  United States
diyAudio Member
 
Join Date: May 2001
Location: Connecticut
Send a message via AIM to Super
You can connect the subwoofer out to the top right RCA jack on the amp. Or, as I have it connected, the left and right speaker out rca jacks from the receiver to the left and right stereo in on the amp. There is no need for a Y cable with this amp.
__________________
Bryan
  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
Volume control on DVD player remote. Lose resolution at low volume? Circlotron Digital Source 2 10th June 2011 07:20 PM
Box Volume is Box Volume, right? skooter Car Audio 5 4th November 2008 05:17 AM
set volume with 50k Pot on Zen V4 cHab Pass Labs 2 17th June 2008 12:49 PM
volume pot william1981 Solid State 5 25th February 2007 10:31 PM
DVC Woofer- Does series vs parallel alter T/S parameters? treedog Subwoofers 11 14th January 2005 01:10 AM


New To Site? Need Help?

All times are GMT. The time now is 03:52 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2