Help with aperiodic enclosure - Car Audio Classifieds!
Car Audio Classifieds!  

Go Back   Car Audio Classifieds! > Enclosures, Fabrication & Sound Deadening > Enclosure Discussion & Design Construction Help

Enclosure Discussion & Design Construction Help Have questions about enclosure design neeed some help thoughout your build, ask here.


Notices

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 08-14-2014, 09:58 PM
CACO Member
 
Activity Longevity
0/20 10/20
Today Posts
0/11 ssssss245
Location: texas
Thanks: 50
Thanked 49 Times in 31 Posts
iTrader: (3)
Feedback Score: 3 reviews
Default Help with aperiodic enclosure

Does anyone here have experience with this type of enclosure? Trying to get some input on it before I waste alot of time and materials and then it doesn't work. First what I am building is mostly for wow factor but I still want it to sound decent. Yes I am prob crazy but thinking of 16 - 20 15" kicker CVR's (I have a new old stock, hook up) inside a quad cab dodge. Box will only have about 1 cu.ft. per sub and going to have the vent thru the floor open to outside. Been researching the size of the vent should equal to half of the displacement of the subs. I know its not the best box for low bass but plan on using an EQ to help out the lows. Again this is for the wow factor of so many subs, I know four ported would be better. I am thinking 6" in the kicks, 12's in the door maybe get really good SQ out of it. I will be running really low power, about 200 per sub.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 08-29-2014, 02:41 PM
CACO Member
 
Activity Longevity
0/20 10/20
Today Posts
0/11 ssssss245
Location: texas
Thanks: 50
Thanked 49 Times in 31 Posts
iTrader: (3)
Feedback Score: 3 reviews
Default

Nobody? Any input?
Reply With Quote Quick reply to this message
  #3  
Old 08-29-2014, 03:06 PM
98GMC's Avatar
Elite Member
 
Activity Longevity
0/20 18/20
Today Posts
0/11 sssss1265
Location: South Dakota
Thanks: 132
Thanked 43 Times in 36 Posts
iTrader: (6)
Feedback Score: 6 reviews
Default

Try DIYMA for Aperiodic.
Reply With Quote Quick reply to this message
 
  #4  
Old 08-30-2014, 01:21 AM
Elite Member
 
Activity Longevity
0/20 20/20
Today Posts
0/11 sssss4405
Location: N. Alabama
Thanks: 296
Thanked 674 Times in 524 Posts
iTrader: (9)
Feedback Score: 9 reviews
Default

Aperiodic (literally "not regular") in philosophy is similar to transmission lines in that the goal is to tame impedance peaks so that the speaker, at least from an electrical POV, does not appear to be in a traditional enclosure at all. As an example of what an ideal aperiodic enclosure should behave like, you can imagine a subwoofer with an extremely low natural resonance in a 1 cubic foot enclosure with a door on the back. As you play higher frequencies, the door is all the way shut, but decreasing in frequency the door opens more and more, so that any measurement of impedance would be riding somewhere on the tail of the resonance spike without ever reaching a peak. The attached picture demonstrates this, in that as you get lower in frequency and the fb peak is pushed lower and lower the impedance stays the same (green line). In reality this isn't possible because it relies on a speaker with no inherent physical properties. There are theoretically other forms of resonance shifting that would make for non-regular behavior; you could even make the same kind of setup but have the door open a random amount for every frequency. This would be aperiodic as well because the impedance graph would be all over the place.

Aside from the classical definition, when talking about real speakers with real mass, aperiodic works in a similar manner, with the ultimate result much like that of the adjustable door, but you still get the characteristic of a sealed enclosure. The goal is to get the characteristic impedance curve of a larger enclosure when the speaker is in a much smaller enclosure than would normally be necessary to get that response. You can do this with an acoustically resistive membrane, but the problem lies in the fact that most membranes have a tendency to act like the randomly opening door. If you just guess on the amount of stuffing you need, you end up with a peaky and wobbly impedance response that looks more like a really leaky sealed enclosure. So to get it sounding right takes a LOT of experimentation, and even then you can't guarantee that you'll ever get a response that sounds better than another type of regular alignment like a simple sealed or vented enclosure.

So since the end goal of going aperiodic is to make the enclosure seem larger than it really is, there's a much more simple answer: use a driver with a slightly lower QTC then you want to end up with and put it in an IB configuration. This shifts resonance down, increasing low end, and assuming the opening at the rear is large enough to not cause helmholtz effects, there's still a slight underdamping effect. None of this is to say you can't add some form of stuffing to the enclosure, in fact it's a good idea for (if nothing else) keeping outside noise from entering the enclosure and exciting the speaker cones.

I don't think stuffing a ton of 15"S in an IB config in a truck is necessarily a good idea, but it will work a hell of a lot better than trying to mess with aperiodic damping.
Attached Images
File Type: jpg aperi.jpg (58.6 KB, 4 views)
Reply With Quote Quick reply to this message
The Following User Says Thank You to SPLEclipse For This Useful Post:
expo615 (08-31-2014)
  #5  
Old 08-31-2014, 11:17 PM
CACO Member
 
Activity Longevity
0/20 10/20
Today Posts
0/11 ssssss245
Location: texas
Thanks: 50
Thanked 49 Times in 31 Posts
iTrader: (3)
Feedback Score: 3 reviews
Default

So can you tune a sealed enclosure with an EQ instead of box volume? Build too small of an enclosure and lose low end efficiency and then just EQ the bottom end and overpower it?

So an aperiodic membrane enclosure is not making the subs sound like they are in a bigger enclosure, just the impedance curve of a bigger enclosure. You would still need an EQ to sound good.
Reply With Quote Quick reply to this message
  #6  
Old 08-31-2014, 11:55 PM
Elite Member
 
Activity Longevity
0/20 17/20
Today Posts
0/11 sssss1411
Location: south FL
Age: 39
Thanks: 66
Thanked 114 Times in 95 Posts
iTrader: (7)
Feedback Score: 7 reviews
Default

Quote:
Originally Posted by expo615 View Post
So can you tune a sealed enclosure with an EQ instead of box volume? Build too small of an enclosure and lose low end efficiency and then just EQ the bottom end and overpower it? - sort of yes but there are limits to how much power you can send to the sub before it is just not effective and or reaches mechanical / thermal limits also factor in the air spring effect on the small box - as the cone trys harder to move in and out at the lower frequencys its atempting to "stretch" the air inside the box for the desired amount of cone travel - so yes more power will attempt to move the cone more but too small of a box will still have limits on the cone travel.

So an aperiodic membrane enclosure is not making the subs sound like they are in a bigger enclosure, just the impedance curve of a bigger enclosure. You would still need an EQ to sound good

- - if the impedance curve stays relatively flat - this means the amp will be sending more constant of a power curve in hz range to the sub.
when the impedance goes up - the power from the amp decreases to the sub

lets say you wired to 2 ohms resting load - and at 40hz the impedance curve spikes up to 4 ohms your amp will be pushing roughly half of its rated 2 ohm power at the 4 ohm load so the sub will be getting much less power during higher ohm values... i believe this is called "box rise" and its just something that happens... there are some ideas about keeping it from going wild but all in all its just something we live with and try not to worry about to much .
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Car Audio Classifieds! forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Location
Where you live
Level of Car Audio Knowledge
What's your level of car audio?

Log-in



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Aperiodic Mats - DIY? USD? Hertz5400LincolnLS Sound Quality Area 8 03-09-2013 07:19 PM
Aperiodic Enclosure Anybody build these? C3 Customs Enclosure Discussion & Design Construction Help 22 02-27-2009 04:58 PM
[COMPLEX] Aperiodic Membranes danteBirosel Tutorials & Quick References 0 11-12-2008 01:45 PM

» Amps
A/d/s/
Advent
Alphasonik
Alpine
American Bass
ARC Audio
Atomic
Audio Art
Audio Gods
Audiobahn
Audiocontrol
Audiopipe
Audison
Aura
Autotek
Avionixx
Bazooka
Beyma
Blaupunkt
Boss
Boston Acoustics
Bravox
Cadence
Cascade (CAE)
CDT Audio
Cerwin Vega
Clarion
Clif Designs
Concept
Coustic
Critical Mass
Crossfire
Crunch
DB Drive
DC Audio
DC Power
DEI
Denon
Diabolo
Diamond
Digital Designs
Directed
DLS
Dual
DYnamat
Dynaudio
Earthquake
Eclipse
Elemental Designs
ESX
Eton
Farenheit
Fi Car Audio
Fix My Speaker
Focal
Fusion
Genesis
Ground Zero
Hafler
Helix
Hertz
Hifonics
Hushmat
Image Dynamics
Infinity
Interfire
JBL
Jensen
JL Audio
JVC
Kenwood
Kicker
Knu Konceptz
Kole Audio
Kove Audio
Lanzar
Lightning Audio
Linear Power
MA Audio
Magnat
Marantz
Massive Audio
MB Quart
McIntosh
Memphis
Metra
MMATS
Mobile Authority
Morel
MTX
Nakamichi
Niche Audio
O2 Audio
Ohio Generator
Optima
Orion
Oxygen Audio
OZ Audio
PG Audio
Phase Linear
Phoenix Gold
Pioneer
Polk
Power Acoustik
Powerbass
Powermaster
Precision Power
Profile
Pyle
Pyramid
RadioShack
Rainbow
Rampage
RE AUdio
Rockford Fosgate
Scanspeak
Scosche
Seas
Sony
soundstream
Sparkomatic
SPL Dynamics
Stinger
Sundown Audio
Swiss Audio
Targa
TC Sounds
TREO Engineering
TRU
Tsunami
Ultimate
US Acoustics
US Amps
Velodyne
Vifa
Viper
Visonik
Xtant
Zapco
Zed Audio
Powered by vBadvanced CMPS v3.2.3
Links
Amp Guts
amplifier, amp guts, ampguts, car audio classifieds, speakers and subs for sale with listings of 12 volt sound systems. Security systems for sale for aftermarket car audio equipment with amplifier and amps for sale
Car Audio Forum
car audio forum, moble audio, car stereo, wholesale car audio, 12 volt, with, amplifier, amp, subwoofer, sound quality, buy car audio, and sell automotive stereo systems for cars
Car Audio Sound Quality Forum
Sound QUality science based car audio forum, amplifier, subs and speaker design, fabrication help, sound systems forum, aftermarket car audio website for sound quality.
Car Stereo Forum
DIYMA car audio stereo forum for 12 volt car audio subwoofer and amplifier systems that have sound quality with wholesale car audio products.


All times are GMT -5. The time now is 06:15 PM.


Powered by vBulletin
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.6.0
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.