Technical Info & How To's

Please note that any open-ended questions are best addressed in the Advanced Discussion portion of the forum. The Technical Info & How To's sub-forum is best suited for articles or time-tested and accurate threads filled with critical information. If a thread from the Advanced Discussion forum happens to prove itself as an integral part of the SSA knowledge base, it will be moved to the Technical Info & How To's forum as a whole, or parsed if necessary. Should any questions arise about this procedure, feel free to send myself or any SSA Tech Team member a pm for further clarification. In summary, we appreciate and encourage any and all questions be asked, but p…

Crest Factor Before we can discuss amplifier headroom, we first need to discuss the music we are listening to. And the concept we need to understand is that of crest factor. Sine waves are the simplest tone. Sine waves are the "test tones" that many people use in this hobby for various reasons, although most likely familiar to everyone as the source used in the typical SPL competition. Sine waves are a periodic waveform. That is, these sine waves or test tones are quite simply a repeating waveform with equal intervals and amplitude in time. Music, in contrast, is very dynamic and transient. Music is a nonperiodic wave form. Meaning music is composed of sounds that frequ…

Disclaimer The first thing I must make abundantly clear is that, though I feel all information listed below is highly accurate, it is possible I am wrong in certain areas. Let’s face it: I’m human. Though the concepts are well understood, much of what I discuss is my interpretation and opinion on a given set of circumstances. I come into this with absolutely zero bias and I feel that gives this more validity than other comparisons of a similar nature that you may have read. Above all, please read in the interest of gaining another viewpoint. Table of Contents 1.0 - Prelude 2.0 - Split-Gap 3.0 - LMT (Linear Motor Technology) 4.0 - Split Coil 5.0 - Efficiency/Flux Effic…

Something I found and is worth having here: A: A: Attenuation, loss of dB. AC (Alternating Current): An electrical current that periodically changes in magnitude and direction. Acoustic Fiberglass: Thin fiberglass material used as damping material inside speaker enclosures. Acoustics: The science or study of sound. Air Gap: The space between the top plate and the pole piece. This is where the voice coil sits. Alignment: A class of enclosure parameters that provides optimum performance for a woofer with a given value of Q. Alpha: In sealed enclosure designs, the ratio of Vas to Vb, where Vb is the volume of the box you will build. Alternator: A device that is turned by a m…

(I am not very active on here but I am on **** and I shared this to SSA at the request of Denim) First off, I want to be clear about one thing. I'm not here to hate on SMD tools. However I am here to help people utilize cheaper and sometimes better equipment suited for the job as well as other jobs. So let's begin with the dd-1. I'm sure most of you know the main competitor to this an oscilloscope. But you might not know why. The SMD dd-1 is 149.99A Velleman HPS140I oscilliscope is 120$ (from Amazon) Here are three ways that the oscope stands alone from the dd-1. The dd-1 does not account for voltage drop. Let's say you set your gain with the dd-1 at 14.4 volts…

http://www.monsterca...tor_Article.pdf DAMPING FACTOR By Richard Clark At a recent AUTOSOUND 2000 manufacturer sponsored seminar, we were asked to comment on the subject of amplifier damping factor. I was extremely surprised to find how much importance was attached to this single specification. Since most folks are a little unclear as to the true meaning of damping factor, we're presenting the following article. First of all, let's discuss the items that enter into the damping factor calculation. At the heart of this calculation is the output impedance of the amplifier. Most all-modern feedback type amps are of the variety known as constant voltage. This means that the…

I love Iron Laws. Why? Well, they are so succinctly and aptly named: they are infact, iron. Good luck breaking them! If you've been a browsing member of the online audio community for a while, you have no doubt heard about Hoffman's Iron Law. What's it all about? Well, it is quite simple. Forgive me if I am misquoting here, but I think JimJ put it best when he said: "You can have low end extension, high efficiency, or small enclosure size. Pick two." Please note that while many people use this statement related to enclosures, it applies to the speaker you're using as well So what does that mean? And why is that the case? Well, as you may have heard me say once …

Here you go guys let me know what you think! What is Google Sketchup? Sketchup is a free 3d modeling program that is made by Google. It is used around the world for its ease of use and accurate function. Where do I get it? Right here: http://sketchup.google.com/download/ Download the basic version. What is the advantage? You can basically "build" your box before you make a single cut! Get an idea what it will look like, even lay out all the boards to make sure you get the most use out of a sheet! How do I use it? Watch my video below! If there is any additional information or questions please let me know!

This is a routinely asked question: "How long does the vent tube need to be if I use an n" flared port?" Granted, there are a few calculators out there that will calculate this for you, particularly if you're using some of the widely available manufactured ports. Here's a good example of a calculator available to you: http://psp-inc.com/psp-inc.com/public_html..._calculator.cgi But what if you have hand-formed your flared ends? Better yet, let's assume you are a dork like me and prefer to hand calculate a lot of things (believe it or not, the extra effort is worthwhile in the long run, but that's a rant for another day). Without getting too into depth on the actual der…

Prior to 1970, there were no easy or affordable methods accepted as standard in the industry for obtaining comparative data about loudspeaker performance. Recognized laboratory tests were expensive and unrealistic for the thousands of individuals needing performance information. Standard measurement criteria were required to enable manufacturers to publish consistent data for customers to make comparisons between various loudspeakers. Thiele-Small Parameters In the early seventies, several technical papers were presented to the AES (Audio Engineering Society) that resulted in the development of what we know today as 'Thiele-Small Parameters'. These papers were authored …

The Big 3 Are: 1. negative battery wire to ground - just replace the negative batt. terminal and wire and ground it to the factory location 2. engine block to ground - replace the ground wire from the engine block to the chasie with a bigger wire (maybe 4 guage) 3. alternator to batt - add a fused wire from the postive post on you alternator (the one comming from the battery) to the postive terminal on your battery. DO NOT exchange wires just add a extra one. make sure it fused the same size as your factory fuse. hope thats helps Note on #2- Some cars have a batt-engine block connection stead of chassis to engine block...

This is always an interesting and controversial topic. Every couple of weeks, a debate rages regarding the relevance of high Xmax and whether it is truly valuable to achieving SPL scores. Perhaps the greatest argument is that Digital Designs Audio drivers, who have a very impressive track record in SPL competition, have been routinely tested to show below average Xmax numbers. How is it possible that a driver with limited linear excursion can still be amongst the loudest? The answer is simple and complex all at once: Xmax is relevant to SPL and it's not. Now that I've confused you, let's proceed. I'll touch on how a speaker makes sound and how it's interpreted at a …

I found this very interesting and decided to post it here to save yall precious clicking time. I probably understood like 65% of the material, but get the basic idea. All of this info is taken from here : http://www.diymobileaudio.com/forum/showth...ht=coustic+xm-6 Mod edit: Thank you to MiniVanMan from DIYMA for putting this together. "There have been a lot of questions of late on the differences between active and passive crossovers. I'm sure with the influx of people on this board there's some confusion over what's what when crossovers are mentioned and how they're employed. So, while this is in no way a comprehensive tutorial on crossovers, it's a beginning. Especial…

Hey, I am thinking of building my 1st sealed sub enclosure for two 8" Orphans from Sound Splinter. I am planning to put it in the trunk of my car (Focus zx3). The trunk measures ~ 41 wide and 30" deep. I believe a single orphan needs 0.186 cu ft (0.178cuft + .08cu ft displacement of the sub) so im assuming (correct me if im wrong) two orphans would need 2x as much, .372cu ft. What I know for certain is that the box needs to be at least 6" deep and be able to fit 2 amps on top (1 mono channel for the orphans and one amp for the speakers). And I would like to be able to easily remove the enclosure when i need a bit of extra space in my trunk, so would something lik…

I have 2 SSa Evil 15s with 4 Stiff Spiders on 2 Crescendo BC5500s in a Hyundai Accent Hatchback Will this 4th Order Wall Design Work? Sealed chamber 3.25 Cubic Feet After Displacement Ported Chamber 6.25 Cubic Feet After Displacement Port 6"wx14"Hx10.25"D Tuned to 45hz (84 Cubic Inch Port Area) Thank you in advance

I have an Alpine SWR-1022D and a SWR-1023D Dual 2ohm woofers. I just checked each woofer. If I wire the two coils in series, I get about 5.6 - 5.8ohm. Parallel is 1.7ohm. Both speakers are very close to being the same coil resistance. I'm just wondering how my Dual 2 ohm coils are so far off from the resistance that they should be. Why such a higher resistance?

As those of you who know me know, I like to do a bit of research before spending any money. In the case of building up my shop supplies, I have diligently compiled a list of tools that will stay the course and provide you with years of service. I thought it might prove beneficial to some of you. Note, I haven

Have you ever completed an enclosure that was a touch too small? Your low end sounds cramped but you don't want to or can't build a brand new enclosure. You throw in some polyfill and are blown away by the improvements. Then you go online to talk about it and everything gets confusing. You don't know why it works or what it really did, but you know that it sounds better. Maybe it's time you learned more about it! Firstly, there are a few primary types of fill that are used. This includes polyester fiberfill, fiberglass insulation, and long-fiber wool. Of these three, polyester fiberfill is perhaps the best option, and also the origination of the term "polyfill". T…

Hey guys, so after posting my orginal video a few months ago about how to design a sub box using Google (Now "Trimble") Sketchup questions started rolling in about some of the more "advanced" features. Which this video to check it out!

Ok so this is the first time I'm amping some mids/highs in my car using a 4 channel amplifier. I have 2 infinity reference 6x9s by an SSL F400. I bought one of those cheap amp hookup kits from walmart just to fill in the gap for wiring I didnt have. (8gauge power and rcas) I got really bad engine noise at first through the 6x9s. I troubleshoot and made a new ground for the headunit to the chastity of the car, also made a new ground for the amp to go to the same ground my battery in the trunk is grounded to. (strut ground) the engine noise was reduced but is still present. everything sounds good, but there is still some audible distortion. I have a pair of stinger bass blo…

I drive a 200 Honda accord and was wondering if i need to do anything special to put the alt in. of course disconnect the battery + and - and let the car sit for a while. the alt is a 200 amp dom iraggi alt and it looks awesome. cant wait to get it installed tomorrow, props to dom, and i hope it is as great as he explained it to be. any tips or tricks to make the install any easier will be very much appreciated. i am mainly wondering if i will need to change anything computer wise to get voltage to where it is supposed to be, or will the computer detect this and regulate it automatically. thanks again. mike.

could one 270 amp alt. charge up my starting battery and 2 kinetik hc3800's or would i need 2 alt?

Ok, so I'm very curious on learning about electronics, and repairing/diagnosing. First, I want to get opinions on where do I need to start. I've read a pretty good bit of info so far, but seem I've limited to what I can learn without doing it. As I'm a more hands on type, only way I can learn and understand is if I do it. And or if I'm confused about something, having somebody connect the dots I'm missing, then it clicks and I understand. So far I haven't found much on actually repairing car audio amps, most is just electronics in general. Which I guess is the same, just seems I get over my head easy because I don't know the basics yet. Basically I'm looking for pointers…

Before installing a power amplifier in your system you should take into consideration the vehicle

copied from the Basic Car audio web site and from FXN A power amplifier takes an input signal, usually a preamp level signal, which has both low current and low voltage characteristics, and produces an output which will have higher current and voltage levels. The power supply available to the audio output IC in a head unit is limited to the battery voltage of the vehicle. This means that the head unit can produce an audio signal with a limited (by the battery voltage) voltage swing, and therefore a limited power output to the speaker. Most amplifiers have a special circuit (switching power supply) to boost the available battery/charging system voltage to a higher voltage…