Less than impressed with L7 and Hifonics Brutus Tuning

[adulbrich 5,000+ posts]

I hope you don't mind me asking, but why is everyone so adamantly against bass boost? Seems odd to me that something the engineers put into the amplifier should be avoided at all costs.
Also, why increase the subsonic?

I've seen audacity before. I'll see if I can figure it out. As for what I was tuning with now, it was just the first video on youtube when you search for "40Hz test tune". It is about 5 minutes long. No idea what decibel level it is recorded at

If you set your gain correctly, you will be getting everything out of your amplifier. Bass boost will only cause clipping from there if your amp is at max output.

I'd raise the subsonic filter to protect your sub. It is a roll-off after the number you have it set at. Because of your box tuning, the box will not protect your sub at lower frequencies.

I'm too tired to really get into details on either of these, sorry

 

[Boomin_tahoe 5,000+ posts]

^^Correct.

Some amp designers do so just to mess with us car audio fanatics. Too much boost/clipping can and will destroy subs, amp.

Does your HU have some sort of loudness button?

 

[LosIsATool 5,000+ posts]

Bass boost can be used as 1 extra band of EQ if you use it properly. It must be set first and the amp tuned to your boost. Basically if you have a dip at 40hz where the bass boost is centered you can flatten out the response with it. You need a RTA to use it right.

 

[Jtyson]

^^Correct.
Some amp designers do so just to mess with us car audio fanatics. Too much boost/clipping can and will destroy subs, amp.

Does your HU have some sort of loudness button?

I have no idea if it has a loudness button. It isn't my car, so my info is limited without having it to look at. What difference do I need to consider when tuning if it does have a loudness option?

If you set your gain correctly, you will be getting everything out of your amplifier. Bass boost will only cause clipping from there if your amp is at max output.
I'd raise the subsonic filter to protect your sub. It is a roll-off after the number you have it set at. Because of your box tuning, the box will not protect your sub at lower frequencies.

I'm too tired to really get into details on either of these, sorry

Okay so I will adjust the subsonic filter to somewhere around 30-35Hz. Would that be correct?

I'm still unsure of what clipping is. I mean I know what it looks like on a sine wave, but by ear, I have no clue. I watched a video on youtube from Sonic Electronix about tuning by ear and assuming he was correct in what he called clipping, in comparison to my situation, even with gain at full tilt, it takes a good twist of the bass boost before the sub makes a similar tonal change, all while increasing in volume and not obviously decreasing sound quality.

Bass boost can be used as 1 extra band of EQ if you use it properly. It must be set first and the amp tuned to your boost. Basically if you have a dip at 40hz where the bass boost is centered you can flatten out the response with it. You need a RTA to use it right.

I'm sorry, but you totally blew my mind with what you said. Maybe it is because it is late, or maybe because I'm a layman, but either way I have no idea what you mean. What would a "dip at 40Hz" be? and bass boost is centered - meaning halfway up/halfway down? What is flattening out response? And what is an RTA?

Sorry I'm not more privy to the nomenclature of the industry. I've been doing it dumb since I got into putting together systems when I was a teen. Just slap stuff together and twist knobs until it sounds good. I appreciate everyone's patience and assistance in explaining this to me simply.

 

[LosIsATool 5,000+ posts]

View attachment 26551383

A real time analyzer.

This is the JBL curve, it is my preferred response.

Say there was a dip at 40hz(that's where most boost are at). You could add boost BEFORE you set gain. That way 40hz will be higher than the rest of the bands and essentially level it out.

 

[Jeffdachef 5,000+ posts]

Okay so I will adjust the subsonic filter to somewhere around 30-35Hz. Would that be correct?

I'm still unsure of what clipping is. I mean I know what it looks like on a sine wave, but by ear, I have no clue. I watched a video on youtube from Sonic Electronix about tuning by ear and assuming he was correct in what he called clipping, in comparison to my situation, even with gain at full tilt, it takes a good twist of the bass boost before the sub makes a similar tonal change, all while increasing in volume and not obviously decreasing sound quality.

dont use loudness, subsonic filter should be set at 75% of your box tuning and if you can gain up safely without distortion then go head, just dont go past 75%, These hifonics amps have a problem with their pentiometer(gain knob) having to be set a lot higher then normal to achieve proper output, other amps you can get full power from 1/4 or 1/3 gain.

Again, go up, until you dont hear it getting louder, then back it off a few notches. Then perform tests with your heaviest bass songs for 5 minutes at a time, see if anything heats up. As long as you keep your eyes, ears, nose sharp, you should have no problem finding the proper spot to get max safe output.

 

[What was that? 10+ year member]

It seems to me you are being a bit to safe. If you have an amp of lesser ability you may have to push it to it's limit or accept it's lesser output. You seem to have an idea of what crap sounds like and common sense so turn the gain up, regardless of dial position, until it starts to sound different instead of louder. Back it of a notch and go. If you're tuned to 40hz your sub sonic should be around 30hz. Do not use bass boost. It only hurts if you don't know how to use it properly. And use your non you tube test tone. Never know how those are recorded. I think you said your hu goes to 60. Set the volume around 45-48. Turn the loud feature on hu to off. After it's all done blast a high bass song for a few minutes and see if anything gets hot or smells funny. If it's still not loud enough check your box tuning. Box volume and port could be off. I wasn't copying everyone, just summarizing everyone's good info in one place so it does not seen so intimadating.

 

[Jtyson]

I appreciate the response. I have no idea when I am going to see the car again. May be a couple weeks. In the meantime, it is turned way down so she won't hurt anything.

I will record my own test tune so that I can be sure of its quality.

As for just going by sound, that is how I originally tuned it before I decided to check on here about how to do it the right way. It sounded good and pounded hard. But, I don't know if it was too much. When you guys say see if it gets hot, how hot is too hot? I've never had an amp that didn't get warm when playing it. Even at reasonably low volumes. And I can't very well tell how hot the sub is considering it is in the box. I don't imagine the dust cap or surround would retain any built up heat.

As for my box tuning, is it possible I gave it too much space? I know kicker recommends about half of what I built. But I read on here in multiple places that the L7 likes a lot of room. I figured the people on here probably know better than the engineers. Why? Because I've never really known many engineers who actually use what they design in real life, so their numbers tend to be more of a theoritcal equasion than a repeated practice. That could be ignorant on my part though.

 

[adulbrich 5,000+ posts]

If the amp is too hot to touch, it is too hot.

 

[Slo_Ride 5,000+ posts]

the box is a bit large. i may of missed... port area?

prolly sounds like sloppy farts after a long night at krystals

 

[LosIsATool 5,000+ posts]

Airspace is right for a square 12. Port area could be wrong.

 

[Jeffdachef 5,000+ posts]

if the cone feels hot to the touch then its too hot, if it feels warm then you are at borderline, you are still fine. The cone DOES retain the heat that the voice coil builds up.

If your amp always gets hot, you might need to do electrical upgrades like the big and a small agm battery in the trunk. Hot amp is a sign of an amp starved for current.

 

[Jtyson]

I've never had an amp too hot to touch. Just warm. Never what I would consider hot, I just wasn't aware of how warm was too warm. As for wiring, I'm sure it would benefit from more, but it is the stock battery, stock alternator, 4 ga wiring to a 5 farad capacitor, then 4 ga wiring to the amp.

I didn't mention the port area, and honestly, I wasn't aware of it when building the box. I just used the calculators on the12volt to calculate port size and length for the desired tuning frequency. Admittedly, this was somewhat of a guesstimate as I was calculating on gross box volume, not net. Gross volume is 4.26ft^3, I figured net volume to be nearer to 3.5ft^3 with corners, port walls and subwoofer considered.

The port is 3.5"x13.5" so 47.25"^2 of area. If my estimate of 3.5ft^3 was close, then I should be okay from what I have read with what I have. However, if I should have calculated it based on gross volume, then I would say it is quite a bit too small.

 

[Jeffdachef 5,000+ posts]

I've never had an amp too hot to touch. Just warm. Never what I would consider hot, I just wasn't aware of how warm was too warm. As for wiring, I'm sure it would benefit from more, but it is the stock battery, stock alternator, 4 ga wiring to a 5 farad capacitor, then 4 ga wiring to the amp.
I didn't mention the port area, and honestly, I wasn't aware of it when building the box. I just used the calculators on the12volt to calculate port size and length for the desired tuning frequency. Admittedly, this was somewhat of a guesstimate as I was calculating on gross box volume, not net. Gross volume is 4.26ft^3, I figured net volume to be nearer to 3.5ft^3 with corners, port walls and subwoofer considered.

The port is 3.5"x13.5" so 47.25"^2 of area. If my estimate of 3.5ft^3 was close, then I should be okay from what I have read with what I have. However, if I should have calculated it based on gross volume, then I would say it is quite a bit too small.

Also what is your box dimensions L X W X H

What is your port length?

You most likely your calculations all off If you are using the 12 volt calculator without doing extra math.

You also go by NET never Gross when you tell others the specs of your box.

 

[Jtyson]

Interesting video on the capacitor. I always assumed it was just like having an extra little battery. I don't entirely understand his test though. Seems to me the results are as they should have been. The capacitor dumps more of a load quickly as designed. Its mAh is far lower than that of the car battery. I guess it bottle necking the voltage during a very large surge would be where it is potentially dangerous for an amplifier correct? But that would be something to be concerned about with a 250+ amp surge. Not something I'd be likely to see with a single 800 watt amplifier I imagine. Also, his 25 amp charger isn't exactly apples to apples with even a small 60 amp alternator. But I get the general idea in how they aren't all they seem and a battery would be a better option.

I believe the box dimensions were 15" tall X 31" wide X 20" deep.