Powering my RSDC102

[Phoenixcolt]

Hey guys quick question. I had the PDX-5 sub channel powering my RSDC102, 300 watts rms, and it was enough for a while, but once I added my Subaru cat back exhaust, I lost a lot of sub sound.

I recently picked up two Tantrum 1200 Refurbs...I only need one so let me know if you need the other one and I can sell it to you.

If I power the RSDC102 with a Tantrum 1200, do you guys think my sub will be a bit more audible over the exhaust? Or do you think it is mostly a result of the frequencies of the exhaust and sub cancelling each other out, and that more amp power won't help much?

I mean with 4 times the rms amp power and hopefully better sq, although I am not sure on that, I would think the sub would be louder but I am not sure what the decibel calculations are...in fact if you can post them, please do.

[stipud]

You'll have to keep the gains way down but yeah you should definitely overcome some of your exhaust.

[Phoenixcolt]

Yeah I figured I wouldn't be able to max out the amp on an RSDc102...I knew I should have just grabbed a Xenon or RSD 600.1 somewhere, but I was Tantrum-struck since I never got to try Tantrum when I was neck deep in Ti Equipment, haha...never got to try Xenon either.

So because the RSDc is 1200 watts peak handling, actually giving it 1200 would be a bad idea I assume.

I am thinking 800 or 1000 watts but those both might be bad choices. What have most people recommended for powering the RSDc's?

I can use the gain formula to set the voltage required for a particular wattage right?

AC Voltage=sqrt(4ohms*Number of Watts)

[stipud]

800-1000w RMS is as much as I would put on one that I wanted to keep for awhile. Yes you can use the DMM method.

[Phoenixcolt]

Thanks, but would your recommendation be 800 to 1000, or a bit lower? I don't want to blow my RSDc, I love it.

[stipud]

On music it will take 800-1k just fine as long as you don't clip or listen at max volume on gangsta rap all the time.

[Phoenixcolt]

No problems there, thanks for the input.

[Phoenixcolt]

Hey guys, I am powering the RSdc with one of my Tantrum 1200s. I know kg mentioned that the Tantrum required an 80amp fuse and it does say that in the manual. I was thinking about how I was expecting more output from this amp even though I only set the gain between 600 and 800 watts, but the bass just doesn't feel like it has much oomph...I feel like the Alpine PDX-5 sub channel had a better bass sound, but of course the Alpine wasn't enough wattage to overcome the exhaust.

I realized a few minutes ago that I have a 60 amp fuse on my power wire. Could this be starving the Tantrum a little bit or would the fuse just have blown if the Tantrum was starving? Could the 60 amp fuse be decreasing the flow of power that the Tantrum depends on and runs optimally on?

[ttocs]

a fuse does not limit the current until you exceed its rating. IF it has not poppped yet, you have not drawn over 60 amps for any length of time. Putting a bigger fuse will not help anything.

[Phoenixcolt]

Yeah I didn't think so, perhaps Subie exhausts are just too loud for my taste...i love the exhaust and all but I never wanted to deprive myself of my bass.

I was adjusting the gain with a multimeter today but stopped at 50 acv because my quarter panels were vibrating so loudly and the sub moving so frantically that I became worried the car or sub were going to be damaged I will try again this weekend and what I am going to do this time is turn the headunit volume up not what looks like 3/4 of the way, but turn it to the loudest my ears would ever be comfortable with in normal listening. This way I will get the amp wattage I calculate at a more realistic listening volume.

You guys think dynamatting the trunk floor would cut down on a good amount of the exhaust noise?

[dwnrodeo]

Dynamat (sound deadener) will not significantly reduce the exhaust noise. Sound deadener does exactly what its name implies, it deadens body panels and prevents vibrations. I have this in my SRT-4 (no mufflers from the factory) and it has no significant impact on the exhaust noise. I would recommend a sound deadener in conjunction with a noise barrier though, something like Second Skin's Luxury Liner Pro. I have this in my Explorer and it significantly reduces road noise.

[Phoenixcolt]

Thanks for the info, this might be exactly what I was looking for, I didn't really think Dynamat would kill that much of the exhaust note. The liner is 40 bucks for 9 square feet before shipping directly from Second Skin.

Can you just lay it in or does it definitely have to be spray glued in like they recommend? Also do you put regular sound deadener under the liner like they recommend just the liner? I am hoping the liner would be enough on it's own so I wouldn't have to deaden as well as line. I already have the factory styrofoam under the trunk floor, I would love to just add the liner under that to see if it makes a difference.

9 square feet is a 25x54 sheet so I will have to see if I can get away with one or will need two. MOst likely I will need 2.

[stipud]

I was adjusting the gain with a multimeter today but stopped at 50 acv because my quarter panels were vibrating so loudly and the sub moving so frantically that I became worried the car or sub were going to be damaged

Yikes! You were supposed to disconnect the sub!

Putting test tones at a speaker for extended periods is not a great idea, especially if you are overpowering them.

Did you turn your headunit down to ~3/4 as well? You need to make sure the headunit output isn't clipping either!

[Phoenixcolt]

I always thought that the amp had to be under load to adjust the gain with a multimeter properly, I thought I even read that...in fact, when I adjusted the gain of the Alpine amp that I just uninstalled, I got a much higher ac voltage with the sub connected than disconnected. When it was disconnected I couldn't even get to the required ac voltage for 300 watts rms.

If I can do it accurately with the speaker disconnected, that would be much much easier.

And yes, I had the headunit volume at 3/4.

[dwnrodeo]

Thanks for the info, this might be exactly what I was looking for, I didn't really think Dynamat would kill that much of the exhaust note. The liner is 40 bucks for 9 square feet before shipping directly from Second Skin.

Can you just lay it in or does it definitely have to be spray glued in like they recommend? Also do you put regular sound deadener under the liner like they recommend just the liner? I am hoping the liner would be enough on it's own so I wouldn't have to deaden as well as line. I already have the factory styrofoam under the trunk floor, I would love to just add the liner under that to see if it makes a difference.

9 square feet is a 25x54 sheet so I will have to see if I can get away with one or will need two. MOst likely I will need 2.

The Luxury Liner has to be spray glued on. I just used the 3M Super 77 spray adhesive. Spray some on the foam, let sit for a bit to get tacky and then apply. You'll have to apply pressure for a bit to get it to stick well. I used deadener under the liner, but you might be able to get away without, not sure. I always tend to err on the overly cautious side because once you get it stuck down, it can be a pain to remove.

[Phoenixcolt]

The quote below is from the sounddomain forum, this is the place I read the info.

I don't know if the info is right but the person was from Elemental Designs at the time so I would hope they knew what they were talking about. I have always done it with the sub connected, not because of this thread, just because that was what I thought was correct since I started using this method...but that doesn't mean I was ever taught right .

Can I disconnect the sub for my adjustment because I will not be dropping the ohms once I add the sub back on and because the Tantrum does up to 1200 solid at 4 ohms? I am just adjusting it to 800-1000 watts.

--------------Hello Guys.

Im the guy from eD in the video.

I would first like to say im sorry for the video not being very professional. We had alot of people asking about it, so we made one very quickly.

The reason we recommed the speaker being hooked up is so that a load is present on the amplifier.

If you have a mono block amp and set the gains to 34 volts with no load, then hook the subwoofer up, that voltage increase due to resistance might be 45 volts and put you into clipping.

Before working for eD I have tested this with an o-scope and can confirm.

While resistance changes depending on frequency, box and other things, its still better to have some type of load on the amp.

The reason that JL audio says not to hook up a load, is becuase their amplifiers are regulated and put out the same power between 1.5-4 ohms. So no load is needed.

I hope this helps our reasoning a little bit.

Alex---------

[Bfowler]

story checks out to me. i have always set my gains with a load

[Phoenixcolt]

story checks out to me. i have always set my gains with a load

Do you think I would still get an accurate result if I set the gain without a load?

[thedeal7235]

I have had 2 rsdc subs(dual 2ohms) since they came out. i had my rsd1200.1 gain set @1400ac volts-=52.91 and NEVER blown one, ever! plese use a 60hz sine wave test tone, subs unhooked, and make sure ur DMM is in ac volts to get the proper reading once u begin to turn the gains up-remmeber, from what i read ur using one rsdc2ohm, correct? then i beleive the tantrum is only going to see a 4ohm load wired series-par., if you wire it parellell to parrellel, youll be below 2ohms, not sure the tantrum to can handle 1ohm loads????? hope i may of helped(right now ive benn testing a mb quart onyx 4125 bridged(class ab ammp) to each of my rsdc subs for 4ohm load, and I STILL LOVE CLASS AB amps for subs, more responsive, to me, hope u get ur output the rsdc subs are THE BEST ive ever had, my audi back window appears to be "boeing " out(also sorry my spelling sucks;)

[stipud]

story checks out to me. i have always set my gains with a load

Do you think I would still get an accurate result if I set the gain without a load?

Now that you've tested it with a load... unhook it and see for yourself! If the voltage stays pretty close to what you set it to, it is fine.

[Phoenixcolt]

I adjusted it without a load earlier and couldn't be more pleased. I got the sound I was looking for.

I do wish I tested it again before I adjusted it though to see if it stayed the same.

[stipud]

Meh whatever, as long as you're happy.

[Phoenixcolt]

Heck yeah...I was starting to worry that something was up with one of the amps but there isn't at all .

[Phoenixcolt]

I would recommend a sound deadener in conjunction with a noise barrier though, something like Second Skin's Luxury Liner Pro. I have this in my Explorer and it significantly reduces road noise.

As an alternative, has anyone ever tried Stinger Roadkill carpet pad(RKCP12)?

I am wondering how well it would work without sound deadening the trunk floor under it. It is a pretty good price on Amazon.

[ttocs]

second skin really is the brand to look at even in if you just go with the standard damplifier IMO. I am getting ready to order some for my stang.