The Great 15" Challenge

[RidnClean 5,000+ posts]

should see if gumby will give up one.

his are just going to sit for months.

 

[negative3five 10+ year member]

SSA should def send a xcon!!!!!!!!

 

[bumpin buick 5,000+ posts]

SSA should def send a xcon!!!!!!!!

If you would like to talk with Denim or Mark about sending one my way, best of luck to you. Denim and I had a fallout on CACO and all though I hold no grudges with him, my intuition tells me that the feelings are not mutual.

 

[SicAudio 5,000+ posts]

Call Mike Stiers @ maxxsonics he might loan you an olympus 1615 and 2415 worth a shot they are pretty sweet subs

 

[John_E_Janowitz 10+ year member]

While I was never asked to have the AV woofers included, a few people have asked if I would be interested in including a driver. There are many huge variables that need to be taken into account if you want to have a valid comparison. First of all, you are comparing drivers. As a result, you need to get all other variables out. Temperature and humidity differences will create differences in the suspension. When Lambda Acoustics and I would measure the same drivers we would measure a large difference in compliance and as a result in Fs from hot humid Florida day to cooler dryer Wisconsin. As a result it should be done in an environment that eliminates this variable or your results wont' be accurate.

As you are comparing woofers alone, I'd highly suggest measuring the woofers out of the vehicle. It is easy for someone to measure the transfer function of their vehicle then and apply it to the results to see what it would be like in their vehicle. It is much more difficult to have to remove a 4runner transfer function first then apply their own.

Measurements should all be done on one day to eliminate possibility of mic placement variables, settings being changed, etc. The other option is to have a control woofer that is measured each time prior to measuring the test woofer. The control woofer results have to match identically to what were measured the previous time. If they don't then the comparisons won't be valid either. Any test needs to have repeatable data.

Even dual 2ohm drivers have a difference in resistance as this is just a "nominal" resistance. Our dual 2ohm AV15H coil is 1.35ohm per coil. This lower resistance allows for more power to be pulled from the amplifier. Most high volume commercial drivers have a DCR close to 2ohm or upwards of 2ohm. They are much closer to 3-4ohm nominal in reality. This is the method they use to prevent burned up coils as higher resistance means less power applied. The point is that you'll need to measure RMS voltage and RMS current to get the amount of continuous power applied.

Again as your goal is to compare drivers, that is what you should be doing. With accurate large signal data, this can translate to any vehicle specific application. Doing accurate distortion measurements at incrementally increasing input levels is going to tell you how clean the woofers will be at low volumes and also at high volumes as issues like non-linear inductance, flux modulation, and thermal issues become more serious. Testing power compression at incrementally increasing levels will tell you how loud the woofer can play as more input power is applied. Once you know these results they can be applied to any vehicle. The vehicle doesn't care which woofer is inside, so the effects from your own vehicle are applied to all woofers the same. If one woofer is 5dB louder with 2000W due to less power compression, that will apply the same in any vehicle.

While the original proposed tests could be fun to play around with and they will give you some results, you won't know the cause for the results. It wouldn't be possible to now if woofer X was really louder than woofer Z or if something in the test changed from this week to the last week.

John

 

[bumpin buick 5,000+ posts]

While I was never asked to have the AV woofers included, a few people have asked if I would be interested in including a driver. There are many huge variables that need to be taken into account if you want to have a valid comparison. First of all, you are comparing drivers. As a result, you need to get all other variables out. Temperature and humidity differences will create differences in the suspension. When Lambda Acoustics and I would measure the same drivers we would measure a large difference in compliance and as a result in Fs from hot humid Florida day to cooler dryer Wisconsin. As a result it should be done in an environment that eliminates this variable or your results wont' be accurate.
As you are comparing woofers alone, I'd highly suggest measuring the woofers out of the vehicle. It is easy for someone to measure the transfer function of their vehicle then and apply it to the results to see what it would be like in their vehicle. It is much more difficult to have to remove a 4runner transfer function first then apply their own.

Measurements should all be done on one day to eliminate possibility of mic placement variables, settings being changed, etc. The other option is to have a control woofer that is measured each time prior to measuring the test woofer. The control woofer results have to match identically to what were measured the previous time. If they don't then the comparisons won't be valid either. Any test needs to have repeatable data.

Even dual 2ohm drivers have a difference in resistance as this is just a "nominal" resistance. Our dual 2ohm AV15H coil is 1.35ohm per coil. This lower resistance allows for more power to be pulled from the amplifier. Most high volume commercial drivers have a DCR close to 2ohm or upwards of 2ohm. They are much closer to 3-4ohm nominal in reality. This is the method they use to prevent burned up coils as higher resistance means less power applied. The point is that you'll need to measure RMS voltage and RMS current to get the amount of continuous power applied.

Again as your goal is to compare drivers, that is what you should be doing. With accurate large signal data, this can translate to any vehicle specific application. Doing accurate distortion measurements at incrementally increasing input levels is going to tell you how clean the woofers will be at low volumes and also at high volumes as issues like non-linear inductance, flux modulation, and thermal issues become more serious. Testing power compression at incrementally increasing levels will tell you how loud the woofer can play as more input power is applied. Once you know these results they can be applied to any vehicle. The vehicle doesn't care which woofer is inside, so the effects from your own vehicle are applied to all woofers the same. If one woofer is 5dB louder with 2000W due to less power compression, that will apply the same in any vehicle.

While the original proposed tests could be fun to play around with and they will give you some results, you won't know the cause for the results. It wouldn't be possible to now if woofer X was really louder than woofer Z or if something in the test changed from this week to the last week.

John

You sure did spend a lot of time on typing this for not reading the purpose behind the testing. Your right this will not be the most accurate test out there as that is near impossible to achieve. Rather I am testing the subs in a set surrounding. I understand not everyone here has a Toyota 4runner.

Lets be honest though most people don't purchase a sub merely because it had tested well in their vehicle. I am simply putting the subs through a similar test to see which ones perform better, which handle power better, which fail, and so on.

Too many people are looking way into this test as if it were the end of the world if I mess something up. Take it for what it is and thats all it is. Not many people have done drop in tests like this so I am providing my time and money to help perform the tests.

I am no noob to the car audio and I understand exactly what I am doing, some people still feel the need to remind me of the variables through posts or PM, I hope everyone can just understand what I am doing. If you guys dont like the results dont look at them, simple as that. I know out of all the people complaining about this though there are still way more people who would love to see the results. Thats the only reason i am really putting up with all of this.

 

[John_E_Janowitz 10+ year member]

You sure did spend a lot of time on typing this for not reading the purpose behind the testing. Your right this will not be the most accurate test out there as that is near impossible to achieve.

15” Heads-up Challenge
Proposal – Collect 15” Dual 2ohm models from several companies to do a variety of tests to compare the subwoofers.

I actually have looked through the entire thread. From your first statement the purpose was to do a variety of tests to compare the subwoofers. Anytime you are comparing something you need to eliminate variables for an accurate comparison. For all the work and effort that you will be putting into this I'm sure people would like to see results that can mean something to them as well.

Lets be honest though most people don't purchase a sub merely because it had tested well in their vehicle. I am simply putting the subs through a similar test to see which ones perform better, which handle power better, which fail, and so on.

Testing in a given vehicle is not specifically a problem. Tom Nousaine always tested every woofer for Car Audio and Electronics in his Corvette. The results were comparable as he would verify the results with a control woofer in each case.

Too many people are looking way into this test as if it were the end of the world if I mess something up. Take it for what it is and thats all it is. Not many people have done drop in tests like this so I am providing my time and money to help perform the tests.

I am not doubting the effort you will put into this. I believe everyone appreciates the work you are willing to put into this. People however need accurate results to make valid comparisons. I am only trying to give you suggestions to help make sure that happens. Will this be taking place in appleton? If so I'm only up the road i Green Bay.

John

 

[bumpin buick 5,000+ posts]

I understand but the simple fact is that there is no possible way to do a 100% full proof test. No matter what anyone says. I am doing a practical, or what I would like to call, a REALISTIC test.

Lets be honest whats the point of having perfect conditions if the people who buy these subs never have the perfect condition. The majority of the clientele still buys pre-fab boxes. So the simple fact that I have 9 boxes being made to a variety of specs is not really necessary for the test either.

Sorry if my words have come off harsh, I am just putting a lot of my time and money into this, I have gotten maybe 100PMs about how inaccurate of an experiment this is. I feel like im back in my high school scientist class, the only difference is now I dont get a grade and I have to pay a ton of money of my own on this.

Testing will be done in Appleton, that is where the o-scope is that I will be using.

 

[roarzorz 10+ year member]

Lets be honest whats the point of having perfect conditions if the people who buy these subs never have the perfect condition.

He's not saying you need perfect conditions. Just identical conditions for each sub. I don't think the intentions here are to rag on you for this but to help with resolving any potentials issues ahead of time.

 

[Ed Lester 10+ year member]

T3 Audio has informed me they are willing to donate a sub for the test.

JD said he e-mailed you about it.

 

[Korn4Life 5,000+ posts]

What I meant about the Square Kicker subs is that you would have to make special enclosures just for them so thats why I figured you wouldnt test them...LOL

 

[rumblebee2 10+ year member]

going to be a very interesting test. i did not skim this threadat all so maybe someone already brought this up... but, wasn't the great 12" challenge set-up the same way?

 

[mlstrass 5,000+ posts]

VERY good input John, thanks for taking the time to explain things. I'm sure Matt picked up a few tidbits that will help him with the testing...

 

[bumpin buick 5,000+ posts]

Just an update, T3 audio is participating in the testing and will be sending me a few subs for testing as well.

 

[allout13 10+ year member]

Just an update, T3 audio is participating in the testing and will be sending me a few subs for testing as well.

which ones? or do you know yet?

you should try contacting konaki to see if you can get a sub from them //content.invisioncic.com/y282845/emoticons/boink.gif.91933e72f927f2cefc79aff02573090c.gif