I have read alot articles online and some places say to leave your speakers wired so the amp sees resistance and some say disconnect them. I trust you guys' knowledge. So should I leave them or disconnect them?
Replies (17)
ttocs on 11/21/2008 13:38:09
I have been sayin for years that it doesn't make sence to me to set your gain via a meter. There are a BUNCH of variables that will just seem to make you setting by what SOUNDS good to you.
I can see using an o-scope but not a meter.
cplkittle on 11/21/2008 15:33:14
If you are using a DMM to set gains, you need your speakers connected for the ohm load. You could use resistors, but you are looking at over 100 VAC in some cases. Here is an excel spreadsheet with an embedded 60Hz test tone. download the file, save the test tone and burn it to a CD, then follow the instructions- it's pretty simple.
http://www.box.net/shared/uchv4dbk88
Victor on 11/22/2008 09:16:39
http://www.clubknowledge.com/Car_Audio_FAQ/?t57
swez on 11/23/2008 05:25:35
The use of a DMM to set gains is a useful tool when the user does not know how to tune by ear.
An "experienced installer" does not need a meter to tell when a given system is pushed beyond its' operating limits. We can hear it and adjust gains accordingly.
As ttocs says, an "O-Scope" is the perfect tool for dialing in a tight system. The best version is a 2-channel scope that allows one to compare input signal waves with output signal waves, all in one test. Unfortunately, most cannot afford a decent O-Scope and best left to the Pros.
Finally, if you have a good O-Scope on hand, I'd bet you can make some side $$ testing and tweaking guys systems. If he's just plunked down $2,000.00 for a new system, $50.00 to dial it all in is money well-spent.
Swez
SQLThump on 11/23/2008 13:32:22
I did a few dial in's with a DMM, and I think it's a waste of time. If you can't effectivly dial in by ear, practice and mess around with it until your sound is optimized to YOUR taste in music. A DMM may measure wattage, but it has no idea if your music sounds good or not.....
ttocs on 11/23/2008 14:26:04
I could only see using a meter to tune a system if you were hard of hearing, which would kinda negate the need for super clean sound. This is also assuming that the person doing it understands and knows how to use a meter and I am amazed at how many people use them and do not understand them...... This is also assuming that they have a GOOD meter that is reading correctly and most of the time I see a meter in a DIY'rs tool box it is a $14 radio shack/autozone special.
So 3 people for it, 2 aginst, isn't there any other opinions?
Victor on 11/24/2008 07:34:45
Yes..
GRIN
Mine ....!
GRIN
2 things....
1 - Gains are not a "Tuning Process" for 'SOUND' ...
Every HU gives out signal at a particular impedance with a definitive voltage.
Every Amplifier input can take a signal supply of a particular voltage at a similar impedance.
When you set gains, these are what you are matching........! It is like setting the sensitivity of the amplifiers input side matching it to the output of the HU ... This is reflected in the increased or decreased voltage by the output rail of the amplifier that shows the effect on the DMM with a particular voltage reading at a particular impedance attached to the output circuit....
Impedance on real time driver loads varies with frequency and we cannot get an error free reading. TRUE too .. So some also advocate the use of dummy loads for a more precise reading...
But lets not get into that one for now...
Gain setting is not a sound tweaking process and cannot be done with EARS...! PERIOD
2 - Tweaking for clean sound requires a detailed and sensitive listener... And sound tweaking support in terms of Various circuitries, say bass boost, EQ, HPF, LPF and software programmings of time delay and phase settings..and using equipments like the O'Scope...
One cannot tune a sound system without EAR'S ......! PERIOD (again)
No Comments...! GRIN
Victor...
newB on 11/24/2008 08:19:35
get'm victor.
i see the OP name is "raiders89" and i'm going out on a limb to say your near Oakland and about 19yrs old
if that is the case i can drive my Oscope out for a few bucks GRIN
if not then just take victors awesome advice and hook it up
-Drew
Victor on 11/24/2008 09:11:20
Advice Vs Statement ... There's a huge difference...
And the above reply was not an advice for sure ...!
newB on 11/24/2008 10:17:01
haha i stand corrected
-Drew
swez on 11/25/2008 10:23:38
Great points Vic! CLAP
Our ears are the bottom line in all of this. However, some need extra tools if they don't have discerning ears and enough experience to dial things in over time.
Most of the Golds here can spot a distortion issue in short order and take care of it in short order. However, some do not have that keen sense that comes from time and experience. They lack the skills of a journeyman installer and cannot tell the difference w/o some extra tools.
For those who lack such skills, the DMM is a low-cost tool to help.
Swez
raiders98 on 11/25/2008 11:37:41
Thanks for all the info guys. For right now Im just gonna set it to what I think sounds good. :)
NewB- Im actually 16 and live in FL lol. Raiders is my school football team. Thanks though
newB on 11/25/2008 13:48:29
89 does not equal 98 lol mybad
GL anyways!!
-Drew
cplkittle on 11/25/2008 15:33:42
Very well stated, victor.
I admit, most of the systems I installed I did set the gain by ear.
I have since learned that there is a small window of potentially damaging square wave distortion that is not audible to the human ear. I agree that an O scope or RTA may be better for dialing in a good balance of sound, but in this case I think we are referring to setting the gain properly for subwoofers.
swez on 11/25/2008 16:28:33
The real problem is not allowing for adequaten "Headroom" when putting a system together. With the "hot cuts" on CD we see in today's music, it's easy to drive amps into clipping w/o hearing that clearly.
What the installer hears as he works, can easily slip into heavy bass distortion on some CD tracks. A skilled installer leaves about +6dB of "headroom" for heavy bass tracks in the Bass Engine. If we don't "dummy proof" the system this way, the user is at risk of dmaging his woofers and sub amp.
One thing I learned in live and DJ club installs, make it "dummy proof" as best as possible. No matter what the DJ does on his mixing board, the amps gains are protected with gain limiters that he cannot override from his mixer. When he tries to go beyond the system limits, the compression circuits block that action and save expensive drivers.
Unfortunately, this feature is not available in mobile audio gear. The installer has to rely on unforeseen and adjust accordingly.
Swez
newB on 11/25/2008 16:36:01
oh- and may i suggest Gain Overlap?
my process for the Oscope goes like this-
play 0db @40hz just shy of clipping and measure output voltage
(in this case 28v)
play -10db @40hz and check output voltage (~8v)
then push up the -10db output voltage to equal the 0db output voltage (28v -10db @40hz)
the reason i do this is because music is not ans strong as a sine wave so when you start playing music you will nave NO clipping BUT it will be very quiet. to compensate- you set the gains with the -10 so that music will be louder- with very little clipping (if any)
SO-
for you i would say just do the process of finding a needed output voltage and using a -10db tone to set the gain as opposed to a 0db tone.
-Drew
PS i skipped the process for measuring when the deck starts to send a clipped signal to the amp because its irrelevant GRIN
PSS i learned this from the head of rockford fosgate- he sent me the CD i use for testing so im pretty confident in the process.
PSSS clipping is less audible at lower freq so he recommends -5db or 0db for mids/highs and -10 for the woofas
swez on 11/25/2008 21:34:28
Exactly the point!
Leave some margin for sharp peaks and allow the system to have some gain overlap for short duration peaks of high energy that are very common in today's music cuts.
I stopped at a local 7-11 for some 1/2 & 1/2 for coffee the next morning. Some dude pulled in next to me with his stereo system booming, got out of his car and left the system on for his buddy to enjoy and annoy others.
Basically, it sounded like "Hammered Dookie Pile". I wrapped up my purchase and headed out the door. He left at the same time and I wanted to thump him on the head for being so inconsiderate. I engaged him in a short conversation, but he barely spoke English and probably a "wetback" Caldean that got a visa to visit family in the area. (Okay, welcome to America dude) We have a lot of them here these days. To each his own is usually my motto. Just don't subject others to it along the way.
Oh well, let the law slap him with a nice fine a few times and he'll get the point. (End Rant)
Swez
Swez
Replies (17)
ttocs on 11/21/2008 13:38:09
I have been sayin for years that it doesn't make sence to me to set your gain via a meter. There are a BUNCH of variables that will just seem to make you setting by what SOUNDS good to you.
I can see using an o-scope but not a meter.
cplkittle on 11/21/2008 15:33:14
If you are using a DMM to set gains, you need your speakers connected for the ohm load. You could use resistors, but you are looking at over 100 VAC in some cases. Here is an excel spreadsheet with an embedded 60Hz test tone. download the file, save the test tone and burn it to a CD, then follow the instructions- it's pretty simple.
http://www.box.net/shared/uchv4dbk88
Victor on 11/22/2008 09:16:39
http://www.clubknowledge.com/Car_Audio_FAQ/?t57
swez on 11/23/2008 05:25:35
The use of a DMM to set gains is a useful tool when the user does not know how to tune by ear.
An "experienced installer" does not need a meter to tell when a given system is pushed beyond its' operating limits. We can hear it and adjust gains accordingly.
As ttocs says, an "O-Scope" is the perfect tool for dialing in a tight system. The best version is a 2-channel scope that allows one to compare input signal waves with output signal waves, all in one test. Unfortunately, most cannot afford a decent O-Scope and best left to the Pros.
Finally, if you have a good O-Scope on hand, I'd bet you can make some side $$ testing and tweaking guys systems. If he's just plunked down $2,000.00 for a new system, $50.00 to dial it all in is money well-spent.
Swez
SQLThump on 11/23/2008 13:32:22
I did a few dial in's with a DMM, and I think it's a waste of time. If you can't effectivly dial in by ear, practice and mess around with it until your sound is optimized to YOUR taste in music. A DMM may measure wattage, but it has no idea if your music sounds good or not.....
ttocs on 11/23/2008 14:26:04
I could only see using a meter to tune a system if you were hard of hearing, which would kinda negate the need for super clean sound. This is also assuming that the person doing it understands and knows how to use a meter and I am amazed at how many people use them and do not understand them...... This is also assuming that they have a GOOD meter that is reading correctly and most of the time I see a meter in a DIY'rs tool box it is a $14 radio shack/autozone special.
So 3 people for it, 2 aginst, isn't there any other opinions?
Victor on 11/24/2008 07:34:45
Yes..
GRIN
Mine ....!
GRIN
2 things....
1 - Gains are not a "Tuning Process" for 'SOUND' ...
Every HU gives out signal at a particular impedance with a definitive voltage.
Every Amplifier input can take a signal supply of a particular voltage at a similar impedance.
When you set gains, these are what you are matching........! It is like setting the sensitivity of the amplifiers input side matching it to the output of the HU ... This is reflected in the increased or decreased voltage by the output rail of the amplifier that shows the effect on the DMM with a particular voltage reading at a particular impedance attached to the output circuit....
Impedance on real time driver loads varies with frequency and we cannot get an error free reading. TRUE too .. So some also advocate the use of dummy loads for a more precise reading...
But lets not get into that one for now...
Gain setting is not a sound tweaking process and cannot be done with EARS...! PERIOD
2 - Tweaking for clean sound requires a detailed and sensitive listener... And sound tweaking support in terms of Various circuitries, say bass boost, EQ, HPF, LPF and software programmings of time delay and phase settings..and using equipments like the O'Scope...
One cannot tune a sound system without EAR'S ......! PERIOD (again)
No Comments...! GRIN
Victor...
newB on 11/24/2008 08:19:35
get'm victor.
i see the OP name is "raiders89" and i'm going out on a limb to say your near Oakland and about 19yrs old
if that is the case i can drive my Oscope out for a few bucks GRIN
if not then just take victors awesome advice and hook it up
-Drew
Victor on 11/24/2008 09:11:20
Advice Vs Statement ... There's a huge difference...
And the above reply was not an advice for sure ...!
newB on 11/24/2008 10:17:01
haha i stand corrected
-Drew
swez on 11/25/2008 10:23:38
Great points Vic! CLAP
Our ears are the bottom line in all of this. However, some need extra tools if they don't have discerning ears and enough experience to dial things in over time.
Most of the Golds here can spot a distortion issue in short order and take care of it in short order. However, some do not have that keen sense that comes from time and experience. They lack the skills of a journeyman installer and cannot tell the difference w/o some extra tools.
For those who lack such skills, the DMM is a low-cost tool to help.
Swez
raiders98 on 11/25/2008 11:37:41
Thanks for all the info guys. For right now Im just gonna set it to what I think sounds good. :)
NewB- Im actually 16 and live in FL lol. Raiders is my school football team. Thanks though
newB on 11/25/2008 13:48:29
89 does not equal 98 lol mybad
GL anyways!!
-Drew
cplkittle on 11/25/2008 15:33:42
Very well stated, victor.
I admit, most of the systems I installed I did set the gain by ear.
I have since learned that there is a small window of potentially damaging square wave distortion that is not audible to the human ear. I agree that an O scope or RTA may be better for dialing in a good balance of sound, but in this case I think we are referring to setting the gain properly for subwoofers.
swez on 11/25/2008 16:28:33
The real problem is not allowing for adequaten "Headroom" when putting a system together. With the "hot cuts" on CD we see in today's music, it's easy to drive amps into clipping w/o hearing that clearly.
What the installer hears as he works, can easily slip into heavy bass distortion on some CD tracks. A skilled installer leaves about +6dB of "headroom" for heavy bass tracks in the Bass Engine. If we don't "dummy proof" the system this way, the user is at risk of dmaging his woofers and sub amp.
One thing I learned in live and DJ club installs, make it "dummy proof" as best as possible. No matter what the DJ does on his mixing board, the amps gains are protected with gain limiters that he cannot override from his mixer. When he tries to go beyond the system limits, the compression circuits block that action and save expensive drivers.
Unfortunately, this feature is not available in mobile audio gear. The installer has to rely on unforeseen and adjust accordingly.
Swez
newB on 11/25/2008 16:36:01
oh- and may i suggest Gain Overlap?
my process for the Oscope goes like this-
play 0db @40hz just shy of clipping and measure output voltage
(in this case 28v)
play -10db @40hz and check output voltage (~8v)
then push up the -10db output voltage to equal the 0db output voltage (28v -10db @40hz)
the reason i do this is because music is not ans strong as a sine wave so when you start playing music you will nave NO clipping BUT it will be very quiet. to compensate- you set the gains with the -10 so that music will be louder- with very little clipping (if any)
SO-
for you i would say just do the process of finding a needed output voltage and using a -10db tone to set the gain as opposed to a 0db tone.
-Drew
PS i skipped the process for measuring when the deck starts to send a clipped signal to the amp because its irrelevant GRIN
PSS i learned this from the head of rockford fosgate- he sent me the CD i use for testing so im pretty confident in the process.
PSSS clipping is less audible at lower freq so he recommends -5db or 0db for mids/highs and -10 for the woofas
swez on 11/25/2008 21:34:28
Exactly the point!
Leave some margin for sharp peaks and allow the system to have some gain overlap for short duration peaks of high energy that are very common in today's music cuts.
I stopped at a local 7-11 for some 1/2 & 1/2 for coffee the next morning. Some dude pulled in next to me with his stereo system booming, got out of his car and left the system on for his buddy to enjoy and annoy others.
Basically, it sounded like "Hammered Dookie Pile". I wrapped up my purchase and headed out the door. He left at the same time and I wanted to thump him on the head for being so inconsiderate. I engaged him in a short conversation, but he barely spoke English and probably a "wetback" Caldean that got a visa to visit family in the area. (Okay, welcome to America dude) We have a lot of them here these days. To each his own is usually my motto. Just don't subject others to it along the way.
Oh well, let the law slap him with a nice fine a few times and he'll get the point. (End Rant)
Swez
Swez
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