So, I started on the Jetta

scottn29 · Post by **scottn29** » Tue Jul 28, 2009 11:41 am

davewaibel wrote:I should be quiet about this, but feel compelled to jump into the shit storm---ttoc I think your taking things a little personally- the majority of your posts come from the side of 'you guys are doing everything wrong'- if that hurts your feelings then I am sorry- but most of us have a limited amount of time and money to spend on our hobby- a no matter what most of us do, it seems to not be good enough for you- its a fine line we walk on the web- most things are perceived negatively- my system gathered more than its share of negative shit, and I took most of it- but personally I don't really care about someone's opinion about something they havent heard. Iasca, and Usac have pretty much disappeared, and the 2 channel purists out there are getting their asses handed to them by every flashing bauble out there with a video screen and sq that is absolute dog shit- go into 99% of the shops out there and ask for their best SQ deck- you will be pointed to an Imprint Alpine deck, or a pioneer deck that they don't stock-arrrrrrrrrrrrrrrrghhhhhh. Their are a few shops in the NW that good audio can be had- one in portland, (500000 people), one in bend (35000), one in salem (50000), wow 3 out of 24 shops- in the guys defense his is trying to keep his vehicle from ringing with out spending 1200 on Dynamat-now aday that about 700 more than most people spend on their complete system- ahhhhhhhhhhhhh- I guess I am done ranting, sorry that its directed at you (ttoc), but most things need to be in perspective, if everything needed to be perfect, no one would ever get their systems done, or would have 20k wrapped up into a 5k car.

I will chime in here and say that he has legitimate points, This stuff is not near the same thing as real deadener, first off its not buytl based, which is way better at lowering the resonace of the panel. Also it is not needed to cover the whole thing with deadener, its just a coplete waste of time and money.

Here is something for you to read up on deadening to learn from, http://www.sounddeadenershowdown.com/cgi-bin/index.cgi

Here is a video of what properly applied deadening will do without covering the whole panel:

http://www.sounddeadenershowdown.com/products/cld

scroll down on the right hand side

Post by **fuzzysnuggleduck** » Tue Jul 28, 2009 1:00 pm

What I've always appreciated the most about Jason and his work is that he's not afraid to try new/different things and to share the experience and knowledge gained through the procedure with us.

Sure, he's not designing new compound to use as a deadener such as actual industry folks are doing with butyl polymers and what not but he is trying something not strictly conventional here (and in many of his other projects) and there is nothing inherently right or wrong with that approach.

And he is very modest about his work, too. It's not like he is professing that this solution is superior to butyl based deadening solutions. He's saying "Hey guys, this is what I decided to do after some research, I'll let you know if it works well or not" and there's nothing wrong with that. He even shares the research he's done with us so we know where he is coming from.

I don't think Jason ever tried to tell us that this is superior or empirically the same or better as the top tier deadening products out there.

I, for one, appreciate that he's willing to try this and let us know how it goes. If it doesn't work well, I'm sure he'll let us know. All that said, ttcos is more than welcome to share his opinions on the use of this product in sound deadening, it's not hurting anyone that he shared his views which by his own account are derived from someone who's involved in the deadening industry.

dBincognito · Post by **dBincognito** » Tue Jul 28, 2009 1:05 pm

I think Jason might want his thread back now.....I don't think this was a sound deadener thread

( Start one if you feel compelled to )

and I don't see Jason wanting to debate this matter.....looks great J.

Post by **ttocs** » Tue Jul 28, 2009 1:08 pm

guys please quit crapping on his post, your just pissin him off and since he rejected my help I politely bowed out. If you want to really know the truth about this stuff and other sound deadoning start another post and I will invite my expert. If you have a problem with the way I approached him or someone else then feel free to pm me.

Until then I really do hope that you guys can hold off buying your own until he can post what has happened. It might take a year or two but I already know what will happen.....

Post by **fuzzysnuggleduck** » Tue Jul 28, 2009 1:22 pm

I have no problem deleting the off topic posts should Jason request that. Pending that request, this is an open phorum.

Post by **Jacampb2** » Tue Jul 28, 2009 2:53 pm

Nah, I'm okay. I'm not pissed either ttocs. If it ends badly, you guys will be the first to know.

Anyhow, back to the progress. I got another sheet of MDF, and am tieing this box up. I am done for the day, but basically I have some filler left to do on the box, interior bracing, and cutting in the 4 ports. The ports are going to be triangular, and will go between each speaker, This isn't going to leave a whole lot of wood left on the face, but it is two layers of 3/4 and my hope is that the ports will stiffen it greatly. I am going to use generous bracing inside.

Here are the pics:

Later,
Jason

Post by **ttocs** » Tue Jul 28, 2009 4:46 pm

glad to know I didn't upset you(for long anyway). That was not the intention I had here or on any of my posts.

Misfire · Post by **Misfire** » Tue Jul 28, 2009 7:35 pm

Great work Jason.... love following your projects!

Post by **Bfowler** » Wed Jul 29, 2009 7:34 am

i love the offroader covered in mdf dust in the back! reminds me of my shop!

Post by **Jacampb2** » Wed Jul 29, 2009 9:27 am

Lol, yeah, I have to get off my ass and finish the Bronco one of these days...

Here is the progress I have made so far this morning. I decided to recut the sub baffle as I was un-happy with it. The new one didn't turn out much better, but I am going to roll with it. I cut in the ports, now I have to make the actual vents. I should have it tied up in a few hours.

Here's the pic:

Later,
Jason

bogart · Post by **bogart** » Wed Jul 29, 2009 10:13 am

Your are on the ball there Jason...looking good my friend...

Post by **fuzzysnuggleduck** » Wed Jul 29, 2009 10:51 am

Looks really nice!

So... is the ZPA 0.8 going to run these subs or what?

bogart · Post by **bogart** » Wed Jul 29, 2009 12:00 pm

oh shit...that would be so so so very badass!!!!

vin78 · Post by **vin78** » Wed Jul 29, 2009 1:10 pm

Nice enclosure you got there

Post by **Jacampb2** » Wed Jul 29, 2009 1:28 pm

Thanks guys!

So, don't you just hate it when your buddy shows up to see what you are up to, helps out doing all the bracing, then say's, you know this isn't going to fit, right? So, we go for a test fit, and guess what, no-fukin'-way she's going in.

So, I did what any rational car audio lover would do, I hauled the box out to the saw horses and cut the heifer in two. It went in, I told him it would fit...

I got a bit ahead of myself, and even in two pieces this bitch was not coming out again. I am going to have to do all the fit and finish work in the trunk. The splice is done with a 5.5" wide piece of .75" MDF. It is generously slathered with wood glue, and securely screwed in place. This thing is extremely tight in there. I had to massage the wheel wells with a 5lb sledge just to ge thte two halves in there. The plan is to lift the box up to the rear deck once the glue in the splices set. This will leave me about 4" under the box for a false floor. I am thinking I may even be able to keep the spare tire in there...

Anyhow, here are the rest of the pics for the day:

Later,
Jason

andy600rr · Post by **andy600rr** » Wed Jul 29, 2009 4:20 pm

Jason, I know that you will have done your homework on this but those ports look awfully small for the volume of air that the three 12's will be moving??

Nice work on the 'gentle pursuasion' of the Jetta

Post by **ttocs** » Wed Jul 29, 2009 5:11 pm

I also thought the area might be a little small but I rarely built ported boxes.

Post by **Jacampb2** » Wed Jul 29, 2009 5:50 pm

First off, the box is built close to RSDc specs, because eventually that is what is going to be in here. The four triangular ports have nearly the same cross sectional area as 3 3" ports as recommended by PG. The box is tuned to 30Hz, the maximum port velocity will be right around 7ft/second.

I was originally going to go with a larger single port, but the larger the port's cross sectional area, the longer in length it needs to be for the same tuning. I rapidly ran out of room inside this box to go with anything much bigger. As long as you don't make the port so small that the velocity goes through the roof, a small port will do the exact same job as a large port. The air displaced remains the same, only the "stroke" of the passive radiator is changed.

The total port area is 21.2in^2, pretty close to PG RSDc specs.

Later,
Jason

knightrider358 · Post by **knightrider358** » Wed Jul 29, 2009 5:55 pm

hey jason how would there not be any sound cancellation with that box so close to the trunk lid. I ask cause I thought subs that close to a wall ie trunk lid can cause the soud waves to cancel each other. I also ask cause I know ull know the answer Im sure u know what u are doing thats pretty self evadent and all. but I know ull have an explanation for me thanx man oh looks freakin awsome man still craving more pics.....

Post by **Jacampb2** » Wed Jul 29, 2009 6:34 pm

Here are some WinISD graphs to show the RSDc SQ ported box specs Vs. my jetta box.

This graph (RSDc Specs out of the manual) shows the port air velocity as well as the tuning Freq and box volume.

This graph, again the PG specs, show the enclosure transfer function, as well as the total port area and length.

This is the air velocity graph for the box designed for the Jetta. It also shows the total port area and length.

This is the transfer function graph for the Jetta box and it also shows the over all enclosure volume and tuning frequency.

Obviously, I tuned mine higher than PG's "SQ" specs, but it is actually somewhere in the middle of the SPL and SQ design. The SPL box is tuned at 50Hz IIRC, so I am a lot closer to the "SQ" spec than the SPL one. Anyhow, you can see port areas are very similar as are air velocities.

Anyhow, I hope that clears up the confusion.

Later,
Jason

Post by **Jacampb2** » Wed Jul 29, 2009 6:45 pm

knightrider358 wrote:hey jason how would there not be any sound cancellation with that box so close to the trunk lid. I ask cause I thought subs that close to a wall ie trunk lid can cause the soud waves to cancel each other. I also ask cause I know ull know the answer Im sure u know what u are doing thats pretty self evadent and all. but I know ull have an explanation for me thanx man oh looks freakin awsome man still craving more pics.....

Actually, exactly the opposite happens. First of all, loading subs against a hard reflective surface is normally a good thing and gives a bit of gain.

If you fire the subs directly into the cabin from the front of the trunk and you can't or don't want to totally seal off the trunk from the cabin, then the waves that travel back into the trunk will tend to reflect off the rear of the trunk and head back into the cabin and be much further out of phase and likely to cancel the front wave.

If you fire the subs back into the back of the trunk, then the two waves tend to reinforce each other instead of canceling.

There has been a lot of contention and a lot of testing done on if and why it makes a difference. Take a look at this web site for an in depth explanation as well as results in several different vehicles. Clicky

Later,
Jason

knightrider358 · Post by **knightrider358** » Wed Jul 29, 2009 7:06 pm

thanx man i knew ud have some good litature for me to read.

I appreciate it and please dont be offended by me asking that I only asked because I never seen facts on the issue. But I knew u would know thanx again

Misfire · Post by **Misfire** » Wed Jul 29, 2009 8:20 pm

Jason, awesome work on the Box. I once miss judged mine in front of the old man. He laughed his ass off, helped me move the box, then cleanly removed the extra 3 inches with his chainsaw. Felt like I was filing those edges for ever to get them smooth. Was very funny though. Keep the pictures coming!

What year is that Bronco? I have a 1996 XLT. That's what I will be installing here as soon as I have a little extra cash!

Post by **ttocs** » Wed Jul 29, 2009 9:19 pm

so what kind of friend was this? The kind that once he told you it would not fit was trying to find a way to help, or was he like me and taking pics, texting the pics and story to other freinds while laughing and pointing at you?

andy600rr · Post by **andy600rr** » Wed Jul 29, 2009 9:41 pm

Jacampb2 wrote:As long as you don't make the port so small that the velocity goes through the roof, a small port will do the exact same job as a large port.

Yep, well aware of this. As I said, I was sure you had done your homework. Maybe the pictures make them look smaller than they actually are. Anyway, eep up the good work!