Phoenix Gold Phorum

i've been told on here by a few guys that the rsd12's should handle a 1200.1 @ 2ohms pretty easily as long as my gains are set correctly. Lately, though, i've read of some experiences people had with them blowing on a sony 1200 and the jbl 1201. These guys didn't sound like the type to have their setting jacked up, so do you suppose those were just anomalies? I definaly trust no one here was steering me wrong on that, i guess i just want someone to reassure that it's all gonna be ok

It's going to be OK. Just don't clip your amp. Clipping a 1200.1 is going to produce big bad power for your woofer. Pay attention to details and make sure you start your tests low and work your way up and watch the results.

Control your gains, know where you are at and the RSd12D4 will be fine.

should i use voltage meter to be on the safe side?...i believe the target voltage for that amp at 2ohm is 44.7

capitolj80 wrote:should i use voltage meter to be on the safe side?...i believe the target voltage for that amp at 2ohm is 44.7

Sure, use a DMM but be sure that all your processors and what not are turned up as far as they ever will be and that your input voltage is set correctly. This way you can be sure that maximum safe output is never exceeded.

fuzzysnuggleduck wrote:Sure, use a DMM but be sure that all your processors and what not are turned up as far as they ever will be and that your input voltage is set correctly. This way you can be sure that maximum safe output is never exceeded.

Good call... even if your headunit isn't clipping the signal, it could be clipping at any other point down your RCA chain. The headunit, linedriver, EQ, etc. could all be clipping. Ideally you need an oscilloscope to set your gains safely. However, since most people don't have those, you have to give your best guess. As such, you typically set things well within their tolerance limits.

For example, set the headunit to 3/4 of it's full output. That should normally be safe, where at 100% it would probably be clipping. Then if your linedriver is safe to 13 volts, try 8 or so. Same goes for any other processor... never max them out, always try to listen for clipping and distortion beyond a certain point, and watch out for clip lights or other clues.

I personally like setting my gains by listening to test tones. It is quite easy to hear when distortion starts affecting a very simple waveform, when it would be challenging on music. I then set my gains to approximately 3/4 of the level where I heard audible distortion at. This normally works better than the DMM method for me, which has sometimes given me a clipped signal from my processors.

sounds good ...i dont have any processors between the amp and h/u...so i'll set my h/u at 3/4 volume (with it's built in eq at the max settings i'll ever have them at) and then set the amp to the target output voltage (44.7). that'll be just over half since i'll have a 5v signal from the h/u and 8v is the max on the amp... I'll do this playing test tones of 20, 60 and 80hz to listen for any distortion...this sound about right?

capitolj80 wrote:sounds good ...i dont have any processors between the amp and h/u...so i'll set my h/u at 3/4 volume (with it's built in eq at the max settings i'll ever have them at) and then set the amp to the target output voltage (44.7). that'll be just over half since i'll have a 5v signal from the h/u and 8v is the max on the amp... I'll do this playing test tones of 20, 60 and 80hz to listen for any distortion...this sound about right?

Not quite...

You want to set your EQ to full flat. You should try to NEVER boost on an EQ, as doing so causes distortion, and can easily trigger your headunit or amp to clip. With an EQ, you should ALWAYS reduce instead. So if you want more bass, the solution is not to raise your bass... but to lower your midrange and treble. This way you will never cause any clipping or awful distortion.

You would also be very lucky if your HU put out 5 volts, if it is rated for 5 volts. I find the RCA output voltage ratings on 99.5% of the headunits in the market to be highly inaccurate. For example, most alpine 4 volt units are lucky to make 2 volts. So just set your gains to wherever the amp will produce it's full power.

The DMM needs a 60hz test tone to properly work. This is because it is the same frequency that our household power works at, so thats what most multimeters are calibrated for. Similarly they need to use 50hz in Europe to get an accurate reading. There are also "True RMS" multimeters, that can read any A/C frequency. These are more expensive.

The method I use with listening for distortion doesn't use a multimeter... I play a 1khz test tone for my front stage and sine sweeps for my sub. I then fuss around with the gains until I get a good undistorted signal. The DMM method is probably initially safer, so I would recommend you start with that.

i gotcha..60hz for the subs and 1khz for the comps...i thought that setting the h/u settings to my listening max would be safer cuz after finishing the setup i'd reduce them to my nominal listening levels, thus giving me head room to increase them a lil on occasion if i felt the need...also...the sub level control, what does it actually "do"..and should that be set right in the middle or as high as i'll use it, then decreased back to normal when the setup is finished?

If you use a DMM you must use 60Hz, regardless of the speaker you will eventually be connecting. This means if you are going to set your front stage with a DMM, you need to turn the high pass crossover off (or set it to below 60Hz), set the gains, and then reset the crossover.

The LPL acts to lower the gain on any channels set to low pass. So to set it the right way, you would have your LPL at max volume before you set your amp gains with the DMM. However, you can also use the LPL as a remote gain knob... assuming you can handle it maturely! To do this you would set it somewhere like the middle, and then set your amp gains. This way for recordings with very little bass, you can increase your LPL beyond the middle to get a bit of additional volume boost. If you recordings have too much bass, there is also room to turn it down as well.

Keep in mind that you can very easily clip your amp by doing this. What I do is I increase the volume until it generally stops getting louder, or it reaches my desired volume, then I turn it back until I notice a drop in volume. That point is normally pretty safe. Listen for stress signs and make sure you turn your LPL down BEFORE you change to some bassier music.

yeah, i had the lpl on my last deck...i dont think i ever had it higher that 7 outa 10. yer a big help...i definaly feel confident that i'll have my stuff set just right now...well, whenever i finish aquiring all the hardware anyway so i can actually get started...gerrr

LPL is a Phoenix Gold specific device, which is basically a rotary knob attached to a phone cord. You can plug it into your amps to control the volume from the dashboard.

LPL is different than subwoofer volume level on the deck, because it limits the volume at the amp. A headunit sub volume control will reduce (or boost) the RCA output voltage instead, which has the same end effect, but with a slightly higher noisefloor. This is because at lower volumes you will have less voltage being passed back to the amps, whereas if you turn down the LPL, you still have your RCAs transmitting at full strength. Minor difference though... I still stick with the LPL because it is easier than navigating menus to change your subwoofer balance. This makes it a much safer bet, since you are more likely to turn it down for bassy music.

I have found that many deck sub volume controls are just shitty boosts. Even the Alpine I tested would clip the signal if I put it above +5 or so. If it's a boost type, you want to leave it at 0. If it lets you REDUCE the volume, then that is a good thing

i see, by decreasing the h/u voltage, you effectively increase the amps sensitivy at a givin setting, thus increasing volume...good to know...how much would the lpl for the rsd1200.1 run me?

oh yeah...the sub control on my old jvc kd-sh77 was good...if it was on 0, you had no bass no matter where the amp was set...the one on my new jvc kd-sh1000 isthe same kind, so i guess i'll have that in the middle when setting my amp gain (around 5 out 10), that way i'll have a lil room either way to move it afterwards.

LPL's are pretty cheap. Usually $10-40. You can ask in the sales section if someone has one to sell. I am not sure where else you could buy one right now... if you do get one though, it would basically replace your headunit volume level control. So you would set this to it's max (unclipped) voltage, and then use the LPL to control the volume instead.

If your JVC deck turns off at 0, then it is likely signal reduction instead of boost. You start getting problems when 0 still puts out the rated volume, and above that boosts it further.

Always reduce, never boost, and you will be clipping free

sounds like im in good shape then ...thnx a bunch stipud