Sub Amp Settings for Heavy Metal

[Bellmeister]

So, Im putting this up as a question but also to help the idk..millions of dudes like me that arent big hip hop boom boom sub guys.
Im into metal and I did a ton of research in the hopes of ending up with a tight bass pop for the double bass drums.I went with an 8" sub Skar SVR series. RP 1200 Watt Skar amp and Skar kerf ported box (if youre a metal head a sealed sub box is better than ported, more controlled tighter bass, I screwed the pooch there a little)
So, the sub is 400 RMS and the amp at 4 ohms is 500 RMS. You have to buy an active LOC for your system if going this route to add volume but 4 ohms is best as far as running coolest and better quality sound then 2 ohm or 1 ohm.
Now, the question at hand. And the tip for metal heads.
The Bass Boost on the amp. Yes the dreaded Bass Boost.
Everyone, everywhere tells you to leave it off. But you have bass boost and you have gain on your amp.
Bass boost boosts just low frequency (bass) while gain boosts all.
8" subs can see LPF setting up to 120hz-130hz cos it can play those higher ones if you want. I have mine at 75hz but use the Bass Boost cos I want the bass to be the main focus and the mid bass to just fill out the music.
So while I am giving this as advice to noob car stereo guys that like metal (cos it freakin works) Im also asking pros out there if this makes sense to you, turning gain down and turning bass boost (-6db) on for my particular set up and music tastes. Thanks

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[LsGuy]

Bass boost usually boosts a specific frequency, and on some amps you can adjust the frequency boosted. The same result can be achieved through box design. I've never messed with bass boost because #1 I prefer a flatter frequency response, and #2 I don't want the boosted frequencies to cause possible clipping

 

[SlugButter]

I’m a metal listener and I run a 15. Nice tight bass. It’s more about the enclosure you have the subwoofer in than anything else. I run my LPF at 70 HZ. You shouldn’t really need bass boost, especially for metal music. Clipping and distortion is what makes metal drums sound muddy and sloppy. Bass boosts will probably make that worse.

 

[hispls 5,000+ posts]

(if youre a metal head a sealed sub box is better than ported, more controlled tighter bass

This is almost entirely untrue and a poor generalization made and repeated by people who don't really understand what is going on or how to build the correct box for their sub. It becomes very poor advice when taken into account that most high power modern subwoofers are engineered to function best in ported alignment.
If your ported box doesn't sound good it is because it is sized wrong, tuned wrong, mounted in a poor location, built poorly, or your subs are not designed to function well in ported alignments.

As far as "bass boost" it is almost always best avoided, but if you can play your favorite music and that makes it sound better to you than it's all good.

 

[Bellmeister]

This is almost entirely untrue and a poor generalization made and repeated by people who don't really understand what is going on or how to build the correct box for their sub. It becomes very poor advice when taken into account that most high power modern subwoofers are engineered to function best in ported alignment.
If your ported box doesn't sound good it is because it is sized wrong, tuned wrong, mounted in a poor location, built poorly, or your subs are not designed to function well in ported alignments.

As far as "bass boost" it is almost always best avoided, but if you can play your favorite music and that makes it sound better to you than it's all good.

What you said, about it being almost entirely untrue and a poor generalization? That's a much more accurate description of what you said. lmao.
Not only do the pros say what I said, but its common sense.
And what you said about high end subs being made for ported these days? Thats not true either.
Ported puts out a wider range of frequencies and will be louder. A sealed box will put out a more narrow range that will be tighter and have a more shallow roll off.
ITs common sense. The port allows for air and more room for the bass to roll off...which will be deeper, louder but less accurate.
My set up sounds really good actually, with metal, but I needed to tell others what I learned afterwards about sealed being tighter.
I dont claim to be an expert but one thing I do a lot of is research.
And I was just trying to save guys a lot of time.

Bass boost btw, I am fully aware that its recommended to leave off.
My system is not set up properly at this time...the gains on amp and LC2i arent set up.Plus I wired at 4 ohms cos its a lot better for theelectrnics and supposedly sounds better. But its not as loud.
So I am trying the -6db bass boost with gain down and it sounds great.

 

[Bellmeister]

I’m a metal listener and I run a 15. Nice tight bass. It’s more about the enclosure you have the subwoofer in than anything else. I run my LPF at 70 HZ. You shouldn’t really need bass boost, especially for metal music. Clipping and distortion is what makes metal drums sound muddy and sloppy. Bass boosts will probably make that worse.

True but I decided to wire at 4 ohms. Volume is lowish

 

[Firewalker]

Okay I will bite as someone who listens to a ton of metal and classic rock who are these "pros". Because hispls has been in this game a very very long time and competes as well. He knows what he is talking about. I've had sealed and ported boxes since I started doing car audio back in the '90s. Ported always sounds better on metal and I've had about 20 different vehicles during that time and several different makers, ported always improved the sound over sealed every time.

 

[ThxOne Premium Member]

2 - 10" subs in a ported enclosure with a 1200w amp @ 1 ohm. Pick your poison:

Slayer, Thomas Dolby, DJ Magic Mike,
Six Feet Under, Radiohead, DJ Bass Boy,
Cannibal Corpse, Marcus Miller, Bass Mekanik,
Metallica, Prince, 2 Live Crew,
Opeth, Daft Punk, NWA,
Pantera, Michael Jackson, Beat Dominator,
Death, Fleetwood Mac, Techmaster,

Two 10's play it all in this ported box. Everything from tight and controlled to floppy and loooowwwww bass. Want to know if your sub(s) are musical... play the entire song Turbo Lover by Judas Priest.

 

[winkychevelle 10+ year member]

What you said, about it being almost entirely untrue and a poor generalization? That's a much more accurate description of what you said. lmao.
Not only do the pros say what I said, but its common sense.
And what you said about high end subs being made for ported these days? Thats not true either.
Ported puts out a wider range of frequencies and will be louder. A sealed box will put out a more narrow range that will be tighter and have a more shallow roll off.
ITs common sense. The port allows for air and more room for the bass to roll off...which will be deeper, louder but less accurate.
My set up sounds really good actually, with metal, but I needed to tell others what I learned afterwards about sealed being tighter.
I dont claim to be an expert but one thing I do a lot of is research.
And I was just trying to save guys a lot of time.

Bass boost btw, I am fully aware that its recommended to leave off.
My system is not set up properly at this time...the gains on amp and LC2i arent set up.Plus I wired at 4 ohms cos its a lot better for theelectrnics and supposedly sounds better. But its not as loud.
So I am trying the -6db bass boost with gain down and it sounds great.

Lol seal boxes play a wider range with a shallower roll off. That's a known fact proven by physics.

Ported boxes have been know to be louder at a specific frequency around the boxes tuning in which resonates with the vehicles acoustics. How flat a ported box plays is entirely up to the design as they can be super peaky one note wonders or quite flat across the board.

I will say ported has the advantage over sealed in that you can cut volume to flatten the response. You can't boost volume without adding clean power assuming the subs can take it.

As far as tight bass, I'd suggest lowering your low pass to 60-70hz and letting you midbass pick up from there to 2600ush hz. Most of that rapid kick drum should be played by the mids anyway since it its a high enough frequency to be localized by the human ear. From a sound stage view point that makes it sound like there is music coming from behind you which your sound stage should be in front of you.

 

[hispls 5,000+ posts]

A sealed box will put out a more narrow range that will be tighter and have a more shallow roll off.

The only part of this that is generally true is the slope of low frequency rolloff but this is why we use a port typically, to add more output below where the sub would otherwise play. Since we can set our F3 at or effectively below any bandwidth we need it can be a useful tool to get "free" low frequency extension.

The port allows for air and more room for the bass to roll off

The port is a Helmholtz resonator and it should be resonating a column of air. If your port is ejecting all the air in it that is called "unloading", this is very undesirable.

What this really boils down to is just picking a high pass "crossover" alignment that works, generally your sealed box will give Butterworth alignment and ported will create Chebyshev. From here what makes sense is to consider your required bandwidth for whatever program material you plan to play and then examine how whatever loudspeaker you're attempting to use will react around that point. If your woofer has an FS of 20hz do you really care if you have greater than -3dB per octave below that? Alternately if your woofer has an Fs of 40hz but you only need to play down to 32hz you may consider it a good tradeoff to get some more output down to 32hz if you don't care what happens below that because you'll never be using it.

one thing I do a lot of is research.

Cool.
Consider these links:
https://en.wikibooks.org/wiki/Acous...Effects_of_the_Port_on_the_Enclosure_Response
This is a good primer on the subject of how variables of a loudspeaker system effect output and how all of this can be expressed as a circuit to predict behavior (these are the formulas that all the box design software uses).

http://web.archive.org/web/20080416...ubwoofer-driver-guide/myths-about-subwoofers/
Excellent clarification of many of these myths Thilo is an absolute train wreck trying to run a business but his understanding of loudspeaker design is among the all time greats.

https://pearl-hifi.com/06_Lit_Archi...ions/Maximizing_Performance_from_LS_Ports.pdf
The often cited Salvatti et al papers concerning loudspeaker ports. Probably the most thorough analysis of the subject ever assembled. I doubt you've ever heard of the names on the paper but you can check those guys' resumes on Linkden to see their credentials.

Of course you don't need to read scholarly articles to prove any of this, just download some free box design software and start plugging and playing with a variety of loudspeakers to see for yourself what is capable of what in what alignments. To put it into better perspective you may want to try to buy a variety of speakers and start building test boxes until you get a good feel of how what you see in those graphs translates to sound in a vehicle, but certainly when you start hitting the extremes in TS parameters the limitations and strengths of certain alignments with those drivers should jump out at even the layman.

Consider many manufacturers do actually put time/effort/money into R&D and you will find a wide variety of strategies to get to the end products. If the answer were as simple as you would make it out, everybody would be doing the same thing and this would all evolve into only a few loudspeaker drivers in only the same few box designs being all we need.

Along those lines, go over to the DD website and read about the "DD Box" and their design philosophy, which, in short, is to start with a box design and then engineer a sub around giving good performance in that box. It's a shame more manufacturers aren't forthcoming about their design process because I'd imagine there's others who start with wanting a driver with some very specific metrics and then building a box around that to get to their definition of "good performance" regardless of what sort of enclosure that will take. And then there's probably everything else in between.

In short though, people who have a lot of builds behind them and who go to a lot of meets and shows are going to call ******** on this whole "sealed box is the only way to play rock/metal" because we've all heard different with our own ears. FFS these bands like Metallica are using Meyer 1100-LFC (bass reflex) at concerts.

 

[Bellmeister]

Okay I will bite as someone who listens to a ton of metal and classic rock who are these "pros". Because hispls has been in this game a very very long time and competes as well. He knows what he is talking about. I've had sealed and ported boxes since I started doing car audio back in the '90s. Ported always sounds better on metal and I've had about 20 different vehicles during that time and several different makers, ported always improved the sound over sealed every time.

Listen, I have a ported box myself. I think for metal...most of it, I can get it to sound great, but after doing a lot of research AFTER I bought the enclosure (duh) the pros in the business say Sealed provides a less loud but shorter, crisper bass response.
Even Crutchfield says..."A sealed enclosure will sound tighter and more accurate."
Now Im no Albert Einstein but tighter and more accurate would seem to me to be what metal heads are looking for. But at same time, a lot of people say otherwise...I dont really know.

 

[Firewalker]

You bought an enclosure. Is it a prefab?

You said "pros" Crutchfield is okay but I wouldn't consider their advice all knowing or even close compared to the some of the people on here and DIYMA. Crutchfield is good for finding out what head units and what speakers fit in stock locations. Same with Sonicelectronix also. But I wouldn't consider them "pros" when it comes to doing custom boxes sealed or ported. All they sell is prefab stuff in boxes.

If you got a prefab then no wonder it sounds like garbage. Try building one for yourself with a box designer and you will understand why we i.e metal heads go ported.

Like I said what "pros", I hope Crutchfield isn't your only "pro" you are talking about.

 

[hispls 5,000+ posts]

Listen, I have a ported box myself. I think for metal...most of it, I can get it to sound great, but after doing a lot of research AFTER I bought the enclosure (duh) the pros in the business say Sealed provides a less loud but shorter, crisper bass response.
Even Crutchfield says..."A sealed enclosure will sound tighter and more accurate."
Now Im no Albert Einstein but tighter and more accurate would seem to me to be what metal heads are looking for. But at same time, a lot of people say otherwise...I dont really know.

At least read the Audiopulse subwoofer myths link. If you are not talking about some specific driver you absolutely cannot make such statements, sure it may work out OK more often than not buying prefab boxes and subs out of the Crutchfield catalog or at the local Best Buy, and for several reasons, but it is a poor place to start trying to find good low frequency reproduction.

Again, take a look at the cabinets used by your favorite bands to play live music, go to a high end home theater store and see how many of their subwoofer systems use vented alignments.

 

[AnthonyO 10+ year member]

I'm not going to get into the whole which enclosure is better ordeal.

Bass Boost: I know some installers that love it, and some that hate it. If you are using an O-scope, DD1, or an amp with smart sense. You can adjust your gain accordingly, by adjusting the bass boost and turning down the gain to compensate for the bass boost. You will see it using one of these tools.

Most people say stay away from bass boost because people dont know they have to lower their gain to compensate for the bass boost. By backing down the gain you eliminate the distortion.

 

[2RZ-FE 10+ year member]

My LPF is set to 80hz-12db on my Pioneer deck and sub amp is set all the way right to 250hz-12db since I can't turn it off. No bass boost on amp and deck.