rpr
Senior Member
- Joined
- Mar 29, 2014
- Posts
- 303
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- 61
- Location
- GA
- Ram Year
- 2014 Ram Limited
- Engine
- Hemi 5.7
I posted this on another forum but for those of you who don't visit that site I thought I would post it here as many of you have been very helpful for my install.
I have taken quite a few measurements off my system and thought it may be helpful for some. Keep in mind all of this applies to a 2014 Ram with the Premium Alpine system, I believe the Premium Alpine system prior to 2013 was different.
There are some differing opinions as to frequency response on the 9 speakers and the sub in this system. While system RTA measurements are helpful, they don't really show what's driving those results, so I started to focus on the strength of the signals being fed to each speaker at different frequencies, as well as the quality of the signal using an o-scope.
The Premium Alpine system has relatively severe changes in voltages being fed to each speaker at different frequencies. So while technically a speaker may have a response at say 1000Hz, it may be anemic at best and effectively not even there in relation to the dB output at other frequencies.
The aggregate frequency response of the whole system is significantly lacking roughly between 650Hz and 1,200+ Hz. Several of us 2014 Ram owners with the Premium system have RTA measurements for the whole system that show a cliff somewhere within this spectrum, although it slightly differs from one truck to the next. Originally I and others thought this was due to the cabin, but after taking quite a few measurements, there appears to be a gap in the signal in this region from the front stage. If you use the rear speakers for summing you can eliminate this, although that may not be ideal for some.
In its simplest terms, overall dB response is dependent on the voltage the factory amp sends to each speaker at varying frequencies. So I found it helpful to measure the actual voltages being sent to each speaker at varying frequencies to get a better feel for what was going on.
If it helps anyone, here are my readings. A good rule of thumb I found when reviewing the below is that you're really not getting much dB output for any speaker output signals that are less than 1V.
Voltages from Factory Amp (2nd number is with Surround Mode On)
The most troubling and uncorrectable aspect of the Premium Alpine system is that the HU (at least mine) begins to clip at a volume of 22 on a scale of 38, and many of the signals are distorted way before they start to clip in a conventional sense. I used an o-scope to measure all the speaker signals, and the dash mids are significantly distorted at 1kHz and below, the rears are distorted throughout their entire frequency range (and these are the closest to a full range signal for summing purposes) and the sub is very distorted below 50Hz. My signal distortion was so bad the dealer was willing to exchange my factory amp. I will be installing it this weekend, but I would actually be surprised if it's much better.
So no matter what you invest in this system, LOC, DSP, etc., there is only so much you can do with it. You can get good results, but if you are an audiophile, you may not be satisfied with it. I had problems with a high noise floor just using the speaker level inputs on my DSP (Bit One) due to the low voltages from the factory amp that requires you to turn up the gains on the amps. I worked around this by adding an LC6I LOC to convert the speaker level inputs to RCAs, and I am now using the RCA pre-ins on the DSP with much better results. Not sure I would recommend this though, as there are too many components each with their own limitations and clipping points and tuning the system is a bear. Any imperfect adjustments will just get compounded downstream.
It's also interesting to note that I've been trying to figure out exactly what the Surround Mode setting does. Based on the above readings, it appears to increase the voltages to all speakers except the rears by 25%. It actually reduces the voltage being sent to the rears by 25%. If I did my math correctly (correct me if I'm wrong here), this translates to a significant increase in RMS power to the speakers in the front stage and the sub (~60%). However, it does change the sound stage significantly if you are using the rears as fill. I tried tuning my system both ways, Surround Mode on and off, and I found better results tuning it with it off. I will still occasionally turn it on depending on the type of music I am listening to. I think the Surround Mode also changes the EQ curves, but I can not confirm that.
One more point, you MUST use your DSP to control the volume on any system with a DSP. The factory amp uses dynamic EQ curves that vary drastically with volume, extremely muddy bass at low volumes and no bass at high volumes. So you need to tune your DSP with your HU at the maximum volume it will play at cleanly (22 on a scale of 38 for me) and leave it there, then tune your system.
Anyway, I hope this helps some fellow Premium Alpine sufferers, and if I'm off base on anything, let me know. Tx.
I have taken quite a few measurements off my system and thought it may be helpful for some. Keep in mind all of this applies to a 2014 Ram with the Premium Alpine system, I believe the Premium Alpine system prior to 2013 was different.
There are some differing opinions as to frequency response on the 9 speakers and the sub in this system. While system RTA measurements are helpful, they don't really show what's driving those results, so I started to focus on the strength of the signals being fed to each speaker at different frequencies, as well as the quality of the signal using an o-scope.
The Premium Alpine system has relatively severe changes in voltages being fed to each speaker at different frequencies. So while technically a speaker may have a response at say 1000Hz, it may be anemic at best and effectively not even there in relation to the dB output at other frequencies.
The aggregate frequency response of the whole system is significantly lacking roughly between 650Hz and 1,200+ Hz. Several of us 2014 Ram owners with the Premium system have RTA measurements for the whole system that show a cliff somewhere within this spectrum, although it slightly differs from one truck to the next. Originally I and others thought this was due to the cabin, but after taking quite a few measurements, there appears to be a gap in the signal in this region from the front stage. If you use the rear speakers for summing you can eliminate this, although that may not be ideal for some.
In its simplest terms, overall dB response is dependent on the voltage the factory amp sends to each speaker at varying frequencies. So I found it helpful to measure the actual voltages being sent to each speaker at varying frequencies to get a better feel for what was going on.
If it helps anyone, here are my readings. A good rule of thumb I found when reviewing the below is that you're really not getting much dB output for any speaker output signals that are less than 1V.
Voltages from Factory Amp (2nd number is with Surround Mode On)
Dash Mids:
0.014 to 0.018 (50 HZ)
0.62 to 0.79V (1KHz)
2.394 to 2.977V (3.5KHz)
3.39 to 4.24V (5KHz)
Front Doors:
5.80 to 7.22V (50 Hz)
0.506 to 0.630V (1KHz)
0.033 to 0.044V (3.5KHz)
0.011 to 0.016V (5KHz)
Rear Doors:
3.42 to 2.76V (50Hz)
5.26 to 4.27V (1KHz)
7.91 to 6.42V (3.5KHz)
8.21 to 6.66V (5KHz)
Sub:
7.76 to 9.78V (50 Hz)
You will see up front that none of the speakers are getting much of a signal at 1KHz. I also took measurements of the front door speakers below 50Hz and they drop off a cliff, so I would not use them for signals between 20Hz and 50Hz, but I did not record those readings. 0.014 to 0.018 (50 HZ)
0.62 to 0.79V (1KHz)
2.394 to 2.977V (3.5KHz)
3.39 to 4.24V (5KHz)
Front Doors:
5.80 to 7.22V (50 Hz)
0.506 to 0.630V (1KHz)
0.033 to 0.044V (3.5KHz)
0.011 to 0.016V (5KHz)
Rear Doors:
3.42 to 2.76V (50Hz)
5.26 to 4.27V (1KHz)
7.91 to 6.42V (3.5KHz)
8.21 to 6.66V (5KHz)
Sub:
7.76 to 9.78V (50 Hz)
The most troubling and uncorrectable aspect of the Premium Alpine system is that the HU (at least mine) begins to clip at a volume of 22 on a scale of 38, and many of the signals are distorted way before they start to clip in a conventional sense. I used an o-scope to measure all the speaker signals, and the dash mids are significantly distorted at 1kHz and below, the rears are distorted throughout their entire frequency range (and these are the closest to a full range signal for summing purposes) and the sub is very distorted below 50Hz. My signal distortion was so bad the dealer was willing to exchange my factory amp. I will be installing it this weekend, but I would actually be surprised if it's much better.
So no matter what you invest in this system, LOC, DSP, etc., there is only so much you can do with it. You can get good results, but if you are an audiophile, you may not be satisfied with it. I had problems with a high noise floor just using the speaker level inputs on my DSP (Bit One) due to the low voltages from the factory amp that requires you to turn up the gains on the amps. I worked around this by adding an LC6I LOC to convert the speaker level inputs to RCAs, and I am now using the RCA pre-ins on the DSP with much better results. Not sure I would recommend this though, as there are too many components each with their own limitations and clipping points and tuning the system is a bear. Any imperfect adjustments will just get compounded downstream.
It's also interesting to note that I've been trying to figure out exactly what the Surround Mode setting does. Based on the above readings, it appears to increase the voltages to all speakers except the rears by 25%. It actually reduces the voltage being sent to the rears by 25%. If I did my math correctly (correct me if I'm wrong here), this translates to a significant increase in RMS power to the speakers in the front stage and the sub (~60%). However, it does change the sound stage significantly if you are using the rears as fill. I tried tuning my system both ways, Surround Mode on and off, and I found better results tuning it with it off. I will still occasionally turn it on depending on the type of music I am listening to. I think the Surround Mode also changes the EQ curves, but I can not confirm that.
One more point, you MUST use your DSP to control the volume on any system with a DSP. The factory amp uses dynamic EQ curves that vary drastically with volume, extremely muddy bass at low volumes and no bass at high volumes. So you need to tune your DSP with your HU at the maximum volume it will play at cleanly (22 on a scale of 38 for me) and leave it there, then tune your system.
Anyway, I hope this helps some fellow Premium Alpine sufferers, and if I'm off base on anything, let me know. Tx.
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