Preout voltage/amp clipping

 

Bronze Member
Username: Infinity_addict

Santa Rosa, California USA

Post Number: 44
Registered: Jul-05
Right, so i have 2 infinity perfect 12 dvq's powered by an infinity REF 1211a. Now i was using a 20hz sample from realmofexcursion.com. In order to keep the amp from clipping i have to put the input (gain) pretty damn low. I did this to ensure my equipment would be protected from songs like late night tip and bass mechanic stuff. Unfortunately, since the input is so low i can't get very loud. I know infinity (esp. in a sealed enclosure) is all about SQ rather than SPL, but it just leaves the low end too weak.

Another unfortunate thing is that my preouts are only 2.2V. My question would be: if i got a HU with higher rated preouts, such as 5V, and i left the input at the same level, would it be louder? Or would i be able to adjust the input higher (thus making it louder) before it started clipping?

thanks!
 

Silver Member
Username: Thrushdtd

New York

Post Number: 263
Registered: May-05
20 hz should not sound that loud from any speaker in my opinion. It is bearily audible. Try a 30 hz sine wave before doing anything else. NO songs go that far below 30 anyway. Late night tip is like 28 i think. Good luck
 

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 8704
Registered: Dec-03
actually I know quite a few songs with notes that center at 20Hz, but that aside, yes use a higher frequency test tone. 35 to 50Hz.
 

Bronze Member
Username: Infinity_addict

Santa Rosa, California USA

Post Number: 45
Registered: Jul-05
i didn't do it so i could bump 20 hz all day, though it is sexy to watch... just didn't want my ish clipping if any of the stuff i listen to happens to get that low (or if i want to show people the 20hz). now i DID adjust the input a little higher so that a 30hz wouldn't clip, but i still wasn't getting the level i wanted. that's why i asked about the preout voltage...
 

Bronze Member
Username: Infinity_addict

Santa Rosa, California USA

Post Number: 46
Registered: Jul-05
could somebody maybe answer my og question, instead of telling me how to set my gains? i just want to know
 

Bronze Member
Username: Infinity_addict

Santa Rosa, California USA

Post Number: 47
Registered: Jul-05
does anybody know?
 

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 8775
Registered: Dec-03
the line voltage has no efect on the system's overall volume, to answer your question.
a higher line voltage means a better SNR, lower THD, and higher resolution signal.. in other words it's cleaner, not louder.

If you want a louder system, get a more powerful amplifier. Having a 4 volt pre-out would just mean the amplifier gain has to be set lower to balance the line voltage and input stage of the amplifier so as not to overdrive the amp into clipping.

BTW, is this a ported enclosure or sealed?
If it's ported or bandpass you don't want to be using a 20Hz tone at all. your subsonic filter on teh sub amp should be set to the tuned port frequency of the enclosure to insure your sub doesn't unload and blow the cone clean out of the driver due to a total loss of damping.
Most boxes aren't tuned any lower than 35Hz for a 12" sub, and about 25Hz for a 15" sub. The box shouldn't be tuned lower than the Fs of those drivers, either.
Sealed.. different story altogether.
 

Bronze Member
Username: Infinity_addict

Santa Rosa, California USA

Post Number: 48
Registered: Jul-05
it's sealed of course.

but now, in getting a more powerful amp, wouldn't i have to keep it turned down anyways in order to not damage things?

way it is right now, the subs are wired series/parallel so i get 4 ohms into one channel. each sub is 400W RMS and the (monoblock)amp is 854W RMS x1 @ 4ohms.
the amp can also put out 1300W RMS x1 @ 2 ohms. so i could give each 650W if i just wired in parallel... what do you think?
 

Bronze Member
Username: Big_lou

Post Number: 54
Registered: Jul-05
How high do you have the bassboost set on that amp? I too have an infinity amp with a low voltage preout and I have to turn the gain down if bassboost is all the way up. Try turning the bassboost to half or lower and then set your gain and give us the results.
 

Bronze Member
Username: Infinity_addict

Santa Rosa, California USA

Post Number: 49
Registered: Jul-05
ok thanks
 

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 8784
Registered: Dec-03
bass boost just increases the input sensitivity.. same thing as turning the gain up, but at a narrow band.. I never use bass boost on an amplifier.
if you want more SPL in your situation it's just time to get better subs I think.
The infinity subs are notoriously weak for output
 

Bronze Member
Username: Infinity_addict

Santa Rosa, California USA

Post Number: 52
Registered: Jul-05
playing with the bass boost didn't help really. what about wiring down to 2 ohms? think it would be ok?
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