Pictures from the 2013 Car Audio Championships

The major car audio organizations recently capped off the year with a joint Finals at the VBCC in Huntsville, AL where both sound quality and sound pressure were represented with a combined 250+ (guesstimate) competitors.  If I had to guess, I’d say there was somewhere around 100-120 SQ competitors alone.  An awesome turnout.

Here are some random pictures from the event (with a few at the beginning thrown in from a tweak and tune before the show).  These are all SQ competitors only.  And they really don’t do justice to the number of cars that were actually competing over the weekend.

 

Subwoofer Testing Coming Soon?

I’ve had a few folks ask me about testing subwoofers.  I had been avoiding subwoofer tests for one main: measurement of Frequency Response, Harmonic Distortion, and Intermodulated Distortion. I can provide LSI data and I think it’s necessary, however I think it’s good to see FR and HD at a minimum as well.

The reason for this is simple: to measure at the output levels to make testing subwoofers/drivers worthwhile, I need to have a mic that can withstand those SPL levels.  My current mic is great for my current set of testing because it doesn’t necessarily require the SPL levels a subwoofer would be pushed to.  The contributing factor here is that subwoofer testing needs to be done in the nearfield so the room’s influence is negated.  Essentially, to raise the signal to noise ratio.  Otherwise the room should be taken out of the measurement by measuring outside far away from any reflective surface.  Audioholics’ site has a great writeup about this here.  I’d like to test a subwoofer in the farfield but I can’t easily do that due to weather and the room I test in.

Therefore, in order to obtain reliable and repeatable subwoofer data at a level that is worth performing the test, I need to do so in the nearfield.  In the nearfield, the SPL level increases by approximately 18dB from 1 meter to ~5 inches (where every doubling of distance is 6dB in output).

Consider that most subwoofer tests are performed in the farfield of at a level of 120dB or more then add 18dB on this for nearfield SPL.  This is why a microphone with high SPL  capability is needed and therefore why those who test subwoofers do so in the farfield.  There really is no explicit right or wrong method of testing a subwoofer in this regard.  However, I believe nearfield testing is paramount to accurate testing within my own criteria and a high SPL capable microphone provides me the opportunity to do this.

Great.. why do you care?  Well, the truth is I am looking for contributions to do this.  I need about $350 to purchase the LinearX M51 Measurement Microphone.  So, that’s my target.  The sooner I am able to obtain the new mic, the sooner I can get started providing even more data.

If you want to help out the site and ultimately the audio community by pitching in a few bucks via the Contribute button at the bottom of the page, it would be greatly appreciated.

Thanks,

Erin

Merry Christmas!

I haven’t posted in a while and just wanted to give a small update.

 

I currently have a few driver tests coming up.  I am working with hometheatershack.com to provide reviews and will be linking those reviews on my site as I go.  This allows me access to some drivers which are typically out of the scope of most of testing.  This allows me to be a bit more diverse in my tests and provide you with more data on drivers you may not be aware of or be curious about.  Up first is the GR Research SW-12-04 Subwoofer and Rythmik A370PEQ Amplifier.  The subwoofer has a dedicated voice coil for the amplifier’s servo feedback circuit.  I have tested the raw subwoofer driver itself and am pleased with the results.  However, this kit’s pudding is the servo system.  I have analyzed and soon will be posting data regarding the subwoofer’s performance with and without the servo circuit active.  Look for that in the next couple weeks.

On deck from my own finances are the Aura Sound NS3 Full Range driver and JL C5-400cm midrange driver.  I have ordered a small bundle of the NS3’s for my own personal experimenting with multiple channel stereo and will be sure to post data from one of them here.  The JL Audio’s C5 line 4″ midrange; the C5-400cm data will be posted sometime in the next month or two, time permitting.  I have been running this driver in my car the past couple months and have been really impressed with the performance in the 250-3khz passband (using LR4 crossovers on each end).  This was one of the few times I’ve ran a driver without knowing how it performs objectively so I’m especially curious to see how my own subjective thoughts compare to the objective data.

As time passes, I will be providing data for drivers such as the Fountek FR88, Scan Speak 18WU, and others.  So, be on the lookout for more data throughout the new year.

 

Thanks for staying with me.

Klippel Me!

The Klippel is here!

I got a package from Klippel today which contained my Distortion Analyzer rack mount unit along with a MI17 microphone, microphone power supply, necessary cables, and literature.  I have taken some pictures of the products and attached them below.  Just click on the image to enlarge the photo. Note the small size of the DA.  It’s dimensions are approximately 19in x 10in x 1.75in and weighs ~6.6 lbs.  Given everything it’s capable of, you’d expect it to be quite large but the Herculean power is all nestled in to a small, somewhat portable box.

You can also see in one of the photos the Calibration Data sheet.  This particular unit was calibrated about 3 weeks ago and shipped out to me last week.

 

Below the photos of the items received today you’ll see some sample data.  As it turns out, I will also be Beta Testing for Klippel and have such been provided with a pre-release version of their new R&D dBLab software.  I’ve only gotten a chance to navigate it for a little bit but so far have found some really nice changes.  The pictures highlight particular changes; such as the way the tables are presented, the calculated assymetry in the Bl Symmetry data plots (and the Kms Symmetry data, not pictured), as well as a user-defined distortion threshold in the Harmonic Distortion data set.  As I begin to use the software for testing, I’ll make sure to note key features of the new version I like (and, if any, ones I don’t particularly care for).

I have some things to do before I can start testing, but it should be up and running within the next few weeks.  For now, enjoy the pics!

 

 

 

Sample Data:

New Table Format.  One thing I like here is the ability to export the data as text and then dump it in to Excel without losing formatting (ie: you won’t have to manipulate the data within Excel to make it usable).

 

Bl Assymetry Chart now has a percentage given to make analysis more efficient.

 

 

The TRF Measurement Module (aka: Frequency Response and HD) now allows for a Fundamental Mean to be set in addition to a threshold for distortion.  This is particularly useful for quickly spotting where distortion may creep up to a point where it’s likely to be audible (ie: -30dB is roughly 3% THD).  Though, keep in mind this threshold isn’t relative to the FR.  It’s absolute.  At least, as far as I can tell right now. 

I need help!

After spending quite a chunk of change on materials and hardware this past week, I’m having to ask for viewer help and support in the way of contributions.

I have updated the site with a contributions link.
You can find it on the right side of the page. Just click on the “contributions” button and it’ll take you to paypal where you can contribute to the site’s funds.

Keep in mind, I am 3rd party. I have none and never will have advertising. Everything I do comes out of my pocket with help from those who contribute. I do not charge for testing. If I did, that would be against everything I am for. My only criterion for testing is that it be applicable to the rest of the community. As long as others benefit from the test, that’s all I need. 😉

If anyone would like to kick over a few bucks my way, it would really be appreciated. I’m working on plans for a new test baffle which is going to cost me a few hundred dollars, as it stands; maybe more. Current plans have it being comprised of steel supports and MDF/plywood and made to be collapsable. I’m still drafting some things I want to do and have learned will be useful from previous iterations. One is the importance of baffle size and storage relationship. There’s a tradeoff here with a static baffle. But, if I can make it a collapsable and mobile baffle, I can have the best of both worlds. My goal is to achieve an IEC baffle again (or very close to it), but when folded down, the size will be be around 5x4x4 ft which is the space allowable in my garage for storage.

The new baffle will also incorporate a foldable microphone stand and a pin/track system allowing the microphone to fold out, and move on a track to various distances from the driver being tested. This gives complete repeatability in FR and HD/IMD testing. Additionally, it makes setup and testing much quicker. No more dragging out the mic stand and measuring distances between tests since I will have the track marked at certain distances. The baffle can also be rolled outside – away from any reflecting surfaces – in order to achieve as close to an anechoic response as possible, allowing for further resolution in measurement. Once measurements are completed, the baffle can be rolled back in and stored out of the way.

I’ll be posting some graphs created from Edge software simulating baffle step/diffraction so everyone is clear on where the baffle influence takes precedent.

I’ll also post pictures of the new baffle build as I go but I probably won’t start for at least another week or two… it’s HOT outside. I think everyone is feeling the wrath lately.

Any funds I receive go toward things such as paying for test equipment I’ve already purchased (such as the Klippel, test microphone, and corresponding modules), materials (such as baffle build materials, cabling, etc), drivers for testing, and shipping costs to return donated drivers to owners when they can’t afford it. I’ll also be saving up to fund the purchase of a laser at some point. All of these add up and every little bit of contribution helps. Contributions as little as a few dollars can add up quickly. So, please, if you can contribute, please do. I hate to plead but I also like to eat. 😉
Thanks,
Erin

Well, maybe not…

Previously I stated I was going to soon be getting a Quality Control unit from Klippel.  Not anymore…

Instead, I am now getting an R&D Distortion Analyzer (DA)!

Currently, my DA is being calibrated and should be shipped to me soon, along with my measurement microphone.  I’ll update the site with pictures and details once everything arrives.

Get ready for some driver data like you’ve never seen.  It just got real…  😉

– Erin

 

I’m back…

Thanks to the folks at Klippel, I’ll be back to testing again with my very own Distortion Analyzer (QC Version) soon.

We’re still working on the details but I wanted to share the good news.

Stay tuned…

– Erin

 

Coming Soon…

Well, you found me before I got off the ground ‘officially’.

I’m actively working to nail down the layout and secure test hardware I will use to provide data and analysis of all sorts of items. In addition, I’ve yet to complete my bio so you can get more acquainted with me and my goals for this site.  Ultimately, I hope to provide you, the audience, with reliable 3rd Party data of car and home audio electronics while explaining how you can do the same at home.  The old ‘give a man a fish’ analogy.

In the meantime, keep checking back.  I should have some goodies coming soon.

– Erin