RE Audio Subwoofer for Sacry DIY Project (1 Viewer)

[BraveHeart123]

I am starting a new DIY sub project for a friend. This would be my second DIY project. The first one (Alpine SWR-1223D) was greatly assisted by Robert, many thanks to him. I tested that sub (tuned @ 25Hz) in my friend's theater room (21x16x12) and it crushed his Def Tech SCRef in every manner in terms of SPL, depth, chest slam, tactile response, and speed both in movies and music. Fired it up with Behringer iNuke 6000 DSP (limited to 1100 watts with an HPF at 22Hz). It is simply ferocious. It handled anything thrown at it with ease even the last 20 minutes from Battle LA. Previously we had the idea of doing away with SCRef and ship SVS PB13 Ultra all the way from US to Pakistan; but hearing the response of Alpine with iNuke we changed the idea. I think if I tune the 4ohms model of it lower @ 20Hz in dual sub configuration, it will easily match or probably exceed the performance of any of the ID big boys. Now over to my actual question; I have access to the complete sub range from RE Audio so I thought why not go for RE instead. The T/S parameters look very promising on paper as compared to the same from Alpine Type R subs. If RE is better than Alpine, which RE model shall I go for?? RE is twice as expensive but if it is better than Alpine, I would go for it and will build one for myself also coz I have tons of power on tap. Expert advice needed. thanx......

 

[schan1269]

I'd buy an RE just because of this one... http://www.reaudio.com/documents/sex_v2_manual[2013].pdf Nothing like putting some SEX in your theatre...

 

[schan1269]

Also depends which RE, there are 11 series to choose from. XXX seems to be their most "lethal"...

 

[BraveHeart123]

Can you explain why you would go with SEX model?

 

[schan1269]

Can you explain why you would go with SEX model?

Purely from a "fun" standpoint. Nothing more. I'd mount it outside the box just so the label could be seen. I bet the "fun" aspect is why it is their best selling(according to them) subwoofer.... I bet a bunch of "well off" kids like having the word right up front and center in the window of their hatchback. (I'd never heard of RE till you brought them up...and I looked at their website)

 

[BraveHeart123]

Purely from a "fun" standpoint. Nothing more.

I was asking purely from performance stand point. Objective is flat response to bare minimum 20Hz and matching or preferably exceeding the performance of PB13 Ultra.

 

[schan1269]

Based on the TS of the 15" XXX...I imagine it would make a mess of a 13Ultra...even if the box you designed wasn't "optimum". I'm not the "sub guru" Robert is...but...I have googled the RE XXX and it has no bad reviews...no matter what size you choose.

 

[Robert_J]

I would not use the RE subs because I have had a long conversation with their former president. He personally went to the Chinese build house and taught them to build the subs. The current owner of RE cuts some corners and their quality is not where it was in years past. Yes, the 18" XXX is an awesome looking driver and if it could actually hit the 54mm xmax without burning up then it would be a great sub. Here's David (the former pres of RE) talking about the newer XXX series - http://www.caraudioclassifieds.org/forum/1361636-post10.html He lives about a 40 minute drive from me and I have 4 of his subs (two 12's, one 15 and one 18). He's a great guy to work with and makes me look like a complete newbie in the subwoofer world.

 

[BraveHeart123]

So could you pls advise on which model to go for? The objective is to crush PB13 ultra just out of rage coz it will cost me more than double its price. Listening to Alpine DIY, I think it is easily achieveable with some better spec sub. So, pls narrow down on top 2 picks from RE. The amp is iNuke 6000 dsp, so 2 ohm DVC are the ones I require for eventual 4 ohm load.

 

[Robert_J]

pls narrow down on top 2 picks from RE

I hope that isn't aimed at me because you must have misunderstood my post. I do not recommend RE subs. If you want more punch, go with an Alpine Type X 15". Those have a ton of copper in the motor to lower inductance and give you great sound quality. The 3" coil will handle more power than the Type R.

 

[BraveHeart123]

Hey Robert yes I completely misunderstood you. Anyway I never meant any offense to anyone esp to you coz I've learned a lot from you. So pardon me if it sounded otherwise. Anyway you recommended Type X 15, but alpine does not have 15" in type x or at least it's not mentioned on their website. They do have 15 in type R but new type R 12" subs (12D4 and 12D2) seem more potent with 1000 watts RMS and 3000 Peak. How about dual 12D4 wired at combined 4ohm load?? How would this setup perform if tuned to 20Hz??

 

[Robert_J]

No offense taken here. I just want to make sure I am understood. I work with a lot of guys from your side of Earth and I understand that a single word can change the entire meaning of a message. I'm not familiar with all of the Alpine offerings so sorry about mentioning a 15. Here's what I meant by a lot of copper - http://www.caraudioclassifieds.org/forum/fix-my-speaker/53560-alpine-type-x-12-yep-alpine.html Adding copper in the motor lowers inductance which increases sound quality and price. This sub rebuild work I link to is by the former president of RE. Multiples of good subs is always a great idea. There are a few white papers on proper setup of multiple subs to even out the in-room response.

 

[BraveHeart123]

Multiples of good subs is always a great idea. There are a few white papers on proper setup of multiple subs to even out the in-room response.

I meant 2 subs in one box. As regards subs located in multiple places.....I am already using 2 and thinking of adding a third one. Bass is never enough.

 

[Robert_J]

2 subs in one box works also. I've done it both ways.

 

[BraveHeart123]

Is there any chance I can tune my current DIY sub lower to 20Hz keeping the box size same? Currently it is tuned to 25Hz with 82L net volume having 4.38" Dia and 18" long round port. I am attaching the response taken with REW and SPL meter at an inch from the center of the sub cone;

Is the response correct? Sonically this sub digs deep with tremendous punch but not in subsonic range. One way that comes to mind is to double the number of ports and lower the tuning frequency to 20Hz. But in doing so WinISD suggests 66" port length. Is that length divided between two ports or is that for each individual port???

 

[Robert_J]

But in doing so WinISD suggests 66" port length. Is that length divided between two ports or is that for each individual port???

That's individual ports, each 66" long. Your enclosure is really a Hemholtz Resonator - http://en.wikipedia.org/wiki/Helmholtz_resonance The math to prove WinISD is on that Wiki page. That's not a bad response graph taken that close to the driver. Because you took it that close, it doesn't factor in the port's response as the driver begins to roll off. At Fb (tuning frequency of the box), 20 hz in your case, the port is creating most of the sound.

 

[BraveHeart123]

Your enclosure is really a Hemholtz Resonator

So what does it translate to in my case? Is it good or bad?? Dont mind my ignorance. 66" is absurdly long port. When I reduce port dia, I do get shorter length but the port velocity hits the roof and tuning also rises. How to resolve this issue?

 

[Robert_J]

It is neither good nor bad. That's the physics behind a ported enclosure and nothing more. You have run into the many trade-offs of a ported enclosure. If you go with smaller ports, you can flare them. Klipsch did both flaring and dimples (like a golf ball) to keep turbulence to a minimum. I've seen one guy do a DIY dimpled, flared port. He also went the way of Polk Audio and used a cylinder inside the port also. It was a neat design and he spent months on it. Most people get tired of the port issues and go sealed or use passive radiators.

 

[BraveHeart123]

Most people get tired of the port issues and go sealed or use passive radiators.

I know sealed is the simplest of all designs, but the ouput drops off way too early. You also run sealed subs. Do you apply eq below 40Hz to raise the low end? If you do apply eq, how much gain do you set in that region??

 

[Robert_J]

Do you apply eq below 40Hz to raise the low end?

Yes. I don't remember. I'd have to check my BFD filters that I set up 7 years ago. My Pioneer VSX-1014 was new when I set up my system.