Skar audio VVX15 8cft box buildness

[Bettr n' Revrse 5,000+ posts]

My thoughts exactly....

Im really confused as to why he would design that?

 

[Why So Cereal? 5,000+ posts]

Im really confused as to why he would design that?

Maybe he thought he was only running 300 rms to it.....

 

[Bettr n' Revrse 5,000+ posts]

That would be the only thing i can think of

 

[Kangaroux 5,000+ posts]

The box design itself, although it seems stupid, will actually perform REALLY well for lows and output (plenty of port area, large box for better low end + efficiency etc.) Now, if the OP plans on running a watt over 300w that thing is gonna bottom out. But if he keeps it around there he will be happy with it I think.

 

[Moble Enclosurs 10+ year member]

Yes, it isn't really a smart thing to take woofers and go over their RMS rating when using boxes this big. That's the great thing about large enclosures, though. They get stupid loud, have a huge response window, and do it on less power than recommended boxes that are usually in the 3-4 cu. range.

Hey guys! I did run across this today and figured I would jump in and hopefully mellow out the concern here lol. So, the main issue noted is that this particular sub will be bottoming out in the design shown. Let me go over this for a minute......

First, as mentioned in the quote above, this is the reason why the design is the way it is, with respect to other factors that were requested. So, looking at the VVX15, you will see that the RMS values are around 600RMS. This is not a driver designed for SPL, though it can compete if you want it to. I want to first point out that I did notice the remarks and replies by the OP and I completely understand the concern and I am not upset about it at all. It just needs a little explanation.

SO, first, one thing I did notice is that the OP was talking about using 1600RMS. Though this is great to utilize more power to gain output, I highly recommend, and have recommended before, that this is not a good idea. As mentioned, the RMS value of the driver is only 600RMS, therefore a calculated voltage used was around 34V.

So, in the order form, it was typed that the driver will be seeing around 1000W. Though this is requested, I will never go over the recommended values of thermal limitations on any design, so 600W was used. And as the quote said above, which is a great point, this design is meant to utilize the drivers low wattage to obtain higher output from increased efficiency.

That is the first thing that has to be mentioned. Now, the OP had emailed me before about the things going on in here, and I looked it over and thought to myself, "They are just opinions and I cant really say anything about that". SO, I let it chill. But now, it is questioning my abilities as a professional acoustical engineer and business owner of a now-popular online company for this particular interest. SO, I have to say something now.

SO, as mentioned, you now know that this design was meant for lower power applications, and I advise that this is followed in any design that I create, unless it is meant for a high power handling, which will never exceed the peak limitations of a driver either.

Second, in the particular design, due to the low coupling of around 30Hz for lowest impedance, it must be noted that the control of the driver will be at stake around the mid30-high 30 range and below about 26Hz. But, at no time, due to using recommended voltage, will this bottom out if used correctly. At that point, it will, and I will consider it user error as it has been mentioned before that this is for high efficiency.

So, this sub will be safely operational in a free air environment of about 21V at its highest excursion point. So, anything above that will need to be compressed to increase that power handling to the recommended 600W(34V) input......and not to exceed that with the exception of the peak rating, which is still figured for in the design.

The thing that needs to be understood about compression in any design, is that as long as a moderate compression exists, there is an increased capability of the driver to operate above its recommendations....and in this case, as mentioned, it was used to increase the safe zone of about 220-250W in free air, to the recommended 600RMS compressed.

We all know that this is not a lot of power for a 15, if you have been around for a while, but if you can use it to increased efficiency, that 600W can in some cases outperform those of higher values, due to the known fact of the effects of increasing power in relation to dB levels.

Now, the mention of Hoffmans law was running about as well. There is a difference of sensitivity and efficiency, so in that respect, the two should not be confused either. SO, now that we have covered that the design is meant to give proper output for a 600WRMS rating, we now know, as expected, that this will be a lower powered design than it was made out to be, and for good reasons.

SO, two things need to be mentioned now that is important for all.

1. OP, do not run over the recommended values of the driver in any situation regardless of box volume. In a smaller box, you increase distortion and possibly decrease the life of the driver...in a larger box, you get overexcursion before any thermal problems will occur in most cases of a good quality built driver.

2. Those who have had their things to say, I cannot stop opinions, which they are seeing as you are not the ones with the information on the design. BUT, you are all right in a sense that the issues mentioned can and will occur if any limitation is purposely reached and challenged.

So, of those two things, we have gathered that no one is wrong about what is going on here. The OP has a highly efficient design that will allow him to use a lower power handling amplifier, which in case may save on money as well, for the same output curve (not SPL) as one with higher power handling. ANd two, that the concerns on here are in fact a part of reality, BUT bashing instead of questioning is not effective either.

From this point on, out of respect, since I have high respect for you all, please come to me if you have any concerns about a design. That would be appreciated and I will have no problem explaining it to you when I get the chance.

 

[Epic0318 10+ year member]

I don't think people where questioning your skills. It was the info the OP was giving that made things so confusing.

 

[-01limited- 10+ year member]

Mobile, op over and over and over said he was going to run 1600 rms to this thing in this big of a box. And as you can see by every reply we told him that box was not built to run that much power. He then chimes in all the time sayin you designed it so its going to be ok. Not one person in here was questioning you, but trying to stop him from destorying his equipment. He acted like you knew he was going to run 1600 to this in that size box and it was ok.

But like I said, if you re-read everyone is telling op he cant run that much power in that big of a box, and he replies with yes I can because a professional designed my box. Thats all there is to it. Obviously OP wasnt listening to a damn thing anyone was saying.

 

[VisceralSound 10+ year member]

Mobile, op over and over and over said he was going to run 1600 rms to this thing in this big of a box. And as you can see by every reply we told him that box was not built to run that much power. He then chimes in all the time sayin you designed it so its going to be ok. Not one person in here was questioning you, but trying to stop him from destorying his equipment. He acted like you knew he was going to run 1600 to this in that size box and it was ok.
But like I said, if you re-read everyone is telling op he cant run that much power in that big of a box, and he replies with yes I can because a professional designed my box. Thats all there is to it. Obviously OP wasnt listening to a damn thing anyone was saying.

In the "quote" I sent I included I'd be using the sk1500.1 at 1ohm, and I don't remember him saying anything about not running it higher than 600, so it was my fault for not understanding correctly thinking he said it would be fine...So now that the elephants out of the room no more discussion of the matter? :V

Lets just get ready for some "LOW POWERED" bass from a big *** box and a single 15!

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[The_Grimy_One 10+ year member]

Run it at 4 ohms and you are good to go!

 

[VisceralSound 10+ year member]

Run it at 4 ohms and you are good to go!

Works, then if I do decide to come down from Cloud 9, I have a lot of room to upgrade to 1 ohm or even strap (with a new box of course)

 

[-01limited- 10+ year member]

In the "quote" I sent I included I'd be using the sk1500.1 at 1ohm, and I don't remember him saying anything about not running it higher than 600, so it was my fault for not understanding correctly thinking he said it would be fine...So now that the elephants out of the room no more discussion of the matter? :V
Lets just get ready for some "LOW POWERED" bass from a big *** box and a single 15!

//content.invisioncic.com/y282845/emoticons/yumyum.gif.0556df42231b304b9c995aefd13928a8.gif

I was just trying to help you out and you was an ass to everyone. There are the laws of physics involved and as you can see in the first few replies in this thread they were brought up. I run the same kind of system as you do. Big box/low power so I'm familiar with it. We was just trying to help you out in not destroying your equipment and you just blatantly ignored our advice.

 

[VisceralSound 10+ year member]

 

[VisceralSound 10+ year member]

Think my wiring method will be okay?

 

[-01limited- 10+ year member]

I mean it makes since you went ahead and made a big enclosure so you could add a second sub, but dont kill your first one too fast =) People have a hard time understanding you can run 300 watts in a big box, or 1600 in a small box and they will perform exactly the same. And also let this be a lesson that yeah, some of us may not be considered "professionals" but we still give good info.

 

[TitoThePirate 10+ year member]

you need to have a new box designed/made

you're going to fry your equiptment if you don't listen.