Tuning queries for Pioneer 7950 and JBL75.4

[vkhandelwal]

I changed the headunit in my car from Sony GTX 550 to pioneer 7950UB. I need to tune 75.4 and 7950 for optimized sound as I feel that the installers in my City are not able to tune the setup properly and the entire setup is underutilized. Also I notice some hissing sound even if I Set equlaizer higher frequencies at very low or last level. this is very annoying when listening to some songs.

Please help!!

[panky12345]

try searching a thread by a member called "Kureti" which discusses how to tune an amp! I could'nt find it.

[vikram18]

Originally Posted by vkhandelwal

I changed the headunit in my car from Sony GTX 550 to pioneer 7950UB. I need to tune 75.4 and 7950 for optimized sound as I feel that the installers in my City are not able to tune the setup properly and the entire setup is underutilized. Also I notice some hissing sound even if I Set equlaizer higher frequencies at very low or last level. this is very annoying when listening to some songs.

Please help!!

Here goes my method
On the HU: set equalizer settings to flat, subwoofer and other related audio gains to zero. Tune your setup at around 90% of the HU's total power. Press pause and increase the volume to full; say if this is 50, tune your system at around 40-45.

Tune your fronts first. with the fader/ balance completely set to the fronts, and the amp gain set to minimum, slowly increase the gain on your amp till the music distorts (use the best CD you have in order to tune this better). set the amp gain just below distortion; where the music is really loud, but does not distort.

Now do the same for your rears. set the fader/balance to rear completely and tune as above. Set the rears a little lower so that they don't overpower your front soundstage but rather fill in.

The HPF for the subwoofer, if you have one, can be set from the HU. 80 will give you the lowest bass, 125, 150 a lot more.

When you tune your system to about 90% of it's output, this ensures that you get distortion free music at any volume.

Hope this helped. Enjoy your music.

[vkhandelwal]

Both headunit and amp has LPF and HPF settings.. I am using 75.4 rear channel in bridge mode and driving the woofer while front are used for front components. rear speakers are directly from headunit.
I have set subwoofer freq on headunit as 80 and LPF as 80
what should be the frequencies and level on amplifier??FLAT for front or LPF as headunit is controlling the LPF..

Appreciate your help...

[navin]

I prefer to use the LPF and HPF of the amp as the settings wotn change if my car goes for servicing.

[panky12345]

again an issue.....so what do the gurus suggest? using settings only on amp or only through HU or a combination of the two? any benchmarks?

[navin]

there are cases when you need to use both (HU and amp) for example for my rear I have a 6.5" woofer mated to a 13cm mid and tweeter. The 6.5" woofer has it's amp and the 5" and 1" use a second amp. So I used the HPF on the HU set to 63Hz then used a 200Hz LPF on the amp feeding the 6.5" and set the HPF on the amp feeding the 5" and tweeter to 150Hz. There is a slight overlap between 150 and 200Hz but since the 6.5" is not directly radiating into the cabin it is filtered.

In my wife's car I was experimenting with various crossover slopes for the front speakers and realised that the best option was using the amp at 100hz/12db (the amp has a fixed slope) and the HU at 63Hz/6db (the HU slope could vary between 6/12/18/24db).

For the rear speakers I do not worry so much. One has to choose between how low the speaker can go and hod audible you want the sub to be. Since I ususally do not like to LPF the sub beyond 80Hz the rear speakers are set to 80Hz too. If the rear speakers are small (4" or less) then a higher frequency might be in order at the risk of having a hole between 80Hz and the higher frequency.

Lastly remember that all these slopes are butterworth not LR so in many cases a hole might not really be so.

[vkhandelwal]

the hissing goes out when I set the input sensitivity at a very low level (almost at the start level). Also I feel the sound is too bright and even the setting the equalizer high freq to the minimum does not work. is it something related to HU as this hissing was absent with Sony HU i was using earlier with same setup???

[navin]

Originally Posted by vkhandelwal

the hissing goes out when I set the input sensitivity at a very low level (almost at the start level). Also I feel the sound is too bright and even the setting the equalizer high freq to the minimum does not work. is it something related to HU as this hissing was absent with Sony HU i was using earlier with same setup???

check speaker phase. if the speakers are out of phse the bass might be canelling out making the setup sound bright.

[vkhandelwal]

Originally Posted by navin

check speaker phase. if the speakers are out of phse the bass might be canelling out making the setup sound bright.

I got the speakers connections and earthing checked and seems to be fine. looke like the noise is being generated by headunit and is being amplified by the amplifer(mainly coming from tweeters). I did not have this with my earlier headunit. is it something related to lower signal to noise ratio??

[clipto333]

Originally Posted by vikram18

Here goes my method
On the HU: set equalizer settings to flat, subwoofer and other related audio gains to zero. Tune your setup at around 90% of the HU's total power. Press pause and increase the volume to full; say if this is 50, tune your system at around 40-45.

hi,

75% of the HU volume is better IMHO as it gives enough room if the recording level of the song is low.

cheers
clip

[panky12345]

Originally Posted by clipto333

hi,

75% of the HU volume is better IMHO as it gives enough room if the recording level of the song is low.

cheers
clip

Clip, how can it be better (i mean tuning at 75% of the volume as opposed 90%)

[vkhandelwal]

Can anybody please respond to the hissing issue. I am sure that professioanal installers and gurus we have in this forum must have experienced this issue before and have resolution/suggestions for this. should I buy a 2 channel amplifier with better S/N ratio for front components or change the head unit again with alpine . the hissing is very annoying sometimes... Please help!!!

[panky12345]

vkhandelwal, follow this:

How to Choose a Noise Suppressor

[DerAlte]

The reasons for the noise, as well as solutions to remove it, are usually fairly simple. Noise suppressors are required when you have established that there IS substantial spurious noise interference from external sources (usually by analysis using oscilloscopes)

In @vkhandelwal's case there could be many reasons (not sure whether he has checked all)
- Unused rear input kept ON in HU config (AUX-IN, iPod, etc.)
- Ineffective grounding of HU chassis
- Ineffective grounding of HU preamp-out socket and RCA cable shield
- Ineffective grounding of amp chassis
- HU-Amp Interconnect cable too long / bad quality / susceptible to electrical interference
- relatively low input signal strength (weak radio signal,
volume of song on cassette/CD/MP3) causing listener to set higher volume