[navin]

Originally Posted by SADesigns

example 1 - 4 ohm speaker set rated at 75wrms, amp rated at 100wrms @4ohms .... here u would use the speakers 75wrms .. and tune the amp such that it puts out 75wrms - this kind of setup is one with dynamic headroom, where your amp will never be pushed to its limits and will perform real clean and stable.........

example 2 - 4ohm speaker set rated at 75wrms, and an amp that puts out 50wrms@4ohms ... here since the amp is capable of producing only 50wrms at its full, it will be foolishness to expect it to produce more clean power ... hence in such a case you should consider the amps rating of 50wrms...

Please note that speaker watt ratings are purely thermal ratings. 100W at 30Hz is a lot different for your speaker than 100W at 300Hz. 100W at 30Hz can damage most 6" midbass drivers even if they are rated to handle 100W thermal power.

[monty9991]

Originally Posted by SADesigns

Its important to know this when you decide on what specs to use for gain setting calculation...

.....

Thanks for the clearifications. your examples are really helpful.
Now know about the gain settings.

[SADesigns]

Originally Posted by navin

Please note that speaker watt ratings are purely thermal ratings. 100W at 30Hz is a lot different for your speaker than 100W at 300Hz. 100W at 30Hz can damage most 6" midbass drivers even if they are rated to handle 100W thermal power.

Yup. 30cycles can do some serious damage to small format speakers, one always needs to keep in mind that proper frequency distribution to individual drivers is very important to achieve clean reproduction of music.

Deciding the cut off freq for each driver depends on its TS parameters.

One can not and one should not expect any driver to faithfully reproduce the entire audible freq range, because there is NO perfect driver.

[ST7677]

I tried setting gain by ear and then measured it with DMM. And I am getting about less than half the voltage of what I was expecting.
The setup does get real loud so no issues that way, but not sure why the readings are coming low.

Asus DX - plays clean till 100% volume, reduced to 85% for use / setting gain

4Ch amp is set to about 5 - half way gain (set by ear) - output is 5.53V per channel
Expected 65W @ 4 ohm, 1 ch = 16.12V


Monobloc is set to about 4.2 - less than half way gain (set by ear) - output is 19.7V per channel (2 channels)
Expected 350W @ 4 ohm, 1ch = 37.4V

[navin]

Originally Posted by ST7677

but not sure why the readings are coming low.

4Ch amp is set to about 5 - half way gain (set by ear) - output is 5.53V per channel
Expected 65W @ 4 ohm, 1 ch = 16.12V


Monobloc is set to about 4.2 - less than half way gain (set by ear) - output is 19.7V per channel (2 channels)
Expected 350W @ 4 ohm, 1ch = 37.4V

1. gain pots might be log not linear
2. the sensitivity of the power amps might be lower than normal (most power amps will reach max output voltage with a 1V signal but some are capable of reaching their max power delivery at 0.5V).

[ST7677]

Thanks Navin,
Yes, the input sensitivity of the amp (as per the manual) is 0.2v-5v.

So is this normal? If yes, would like to understand why the voltage would be so much lower, than the computed volume.

Also I used 5 songs* to set the gains. I stopped at point where 1st song (with highest level) started sounding different and then turned down slightly.
(*Centrafuse lets you swap between the loaded songs quickly)

[SADesigns]

One does not set gains on songs..... it should be done on a test tone....


Note from the Team-BHP Support Team : Please take the time to use proper punctuation as per Team-BHP rules. Avoid...typing...like...this. Thanks.

[abhipuru16]

This is when we are tuning for SQ purposes. What about SPL?
Do we here change the LPF and HPF settings?
What about bass boost and Subsonic Filter?

[trumpet]

Originally Posted by gunbir

Can you please elaborate on this? I find this most interesting...

Hi everyone,

Please check out MLP (Meridian Lossless Packing). This is a standard on DVD Audio that looks at compression differently from the compression packs we are familiar with today. In a nutshell, this standard analyses the waveform (in its musical context - meaning it looks at the music as a series of musical notes like semibreves, crochets, minims etc) and then uses compression to achieve and store what is actually necessary. Please check the below link.

DVD Benchmark
This technology was around atleast 5-6 years back. I remember reading it online.The difference to this approach is (at a very high level) recreating sheet music from a wave file or an mp3 file (or almost like it).

[Maky]

Hello Everyone,

I'm trying to set Gain(38.72V) on my JBL Monoblock. I purchased a Multi-meter for this purpose and now need some help.
Following is the image of the product I purchased:

-I would like to know which of the 3 holes on the Multi-meter does the Black wire go into and the which one the Red goes into?

-Which setting should the dial be at for measuring Volts for the Amplifier?

Thanks : )

[DerAlte]

Originally Posted by Maky

... which of the 3 holes on the Multi-meter does the Black wire go into and the which one the Red goes into? ...

The black wire goes into the center hole COM, and the red wire goes into the right most hole - VΩmA.

Originally Posted by Maky

... -Which setting should the dial be at for measuring Volts for the Amplifier? ...

V~ 200.

[Maky]

Originally Posted by DerAlte

The black wire goes into the center hole COM, and the red wire goes into the right most hole - VΩmA.

V~ 200.

Thanks DerAlte.
One more question, I set it using everything to Off or Flat, except LPF to 80Hz but The SUB option on my Head Unit offers a range from -6 to 0 to +6. Which do I pick of the three : S ?

[DerAlte]

Originally Posted by Maky

... I set it using everything to Off or Flat, except LPF to 80Hz ...

Good.

Originally Posted by Maky

... but The SUB option on my Head Unit offers a range from -6 to 0 to +6. Which do I pick of the three : S ?

Three? Isn't it -6 to +6dB in steps of 0.5 or 1dB?

Keep it at zero in your current tuning. The sub boost (it is tied to Sub Out) will be for those times that you want to boost low bass a bit more. Set it to +1 or 2dB at those times, and bring it back to 0dB (no boost) at other times. IF the rear seat passengers get nauseated and complain about the boom boom, set it to -6dB!

[Maky]

Originally Posted by DerAlte

Good.

Three? Isn't it -6 to +6dB in steps of 0.5 or 1dB?

Keep it at zero in your current tuning. The sub boost (it is tied to Sub Out) will be for those times that you want to boost low bass a bit more. Set it to +1 or 2dB at those times, and bring it back to 0dB (no boost) at other times. IF the rear seat passengers get nauseated and complain about the boom boom, set it to -6dB!

A range yes.
Steps of 1 unit so -6,-5,-4....0,+1,+2 etc. I've tuned it at 38V at 0 SUB on the HU. It allowed me to set the gain knob a little bit higher than on the +6. It's now at 1/4th.

Can't say I'm satisfied with the Morel Ultimo SC bass response....
Maybe after it breaks in after a couple of weeks. Had it running for only a week's worth of play time now.

[DerAlte]

Originally Posted by Maky

... Can't say I'm satisfied with the Morel Ultimo SC bass response....
Maybe after it breaks in after a couple of weeks. Had it running for only a week's worth of play time now.

Try re-positioning the sub, i.e. facing rear, then side, then front. In some positions it will sound better than in the others. Another way is to use Time Alignment, if available in the HU.