Its tuning time! A journal with lots of errors and little success.

[Trepkos 10+ year member]

Warning! Lots of reading, numbers, and questions.

Not saying that this is the best and most proper way to tune your system but Ive had my system installed for the past two weeks and Ive been playing around it a bit, never coming to a satisfactory sound and ofcourse Im a complete novice to the subject and any and all friends who run systems in this area usually run theirs with their bass boost on max and gains maxed as well, so no real knowledge to be found in this area.

But in this process, I will be using the following to set the gains, pass filters, and other small details including HU settings to see if I can get the safest, most satisfactory, and also best sounding/loudest optimal performance from my system.

Now there will be problems that I will run into and thats the reason I am posting this as in depth and careful as possible to help and receive help as these problems arise.

Tools I will be working with:

80gb Ipod Classic(Will be using this for music playing ability)

Test Tone CD(10-300hz)(This will be used for selecting playing frequency as well as gains setting.)

DMM(Will be used for measuring impedance, DC Vs, and AC Vs)

Calculator for adjusting different knobs on the amplifier.

Notepad for taking notes.

And assorted tools for disconnecting speaker terminals and adjusting knobs.

The equipment is in my signature. And I will be using a digital camera and camcorder to record every progress made.

Woo, Amplifier Setting!

First up, we're going to set the different settings on the amplifier besides the gains/level/sensitivity knobs. This will mainly be the different filters, phase, and other options.

First, we're going to start with the Hifonics 1606d mono-channel amplifier. The subwoofer is a 15" Fi Q DVC 2-Ohm subwoofer which is wired in parallel to 1-ohms. Since the Hifonics amplifier is 1600watts @ 1-ohms and also overrated, it should be a perfect match for the slightly underrated yet 1000watt thermal handling of the 15" Fi Q.

The 15" Fi Q is sitting in a box at approx. 3.35ft^3 with a port that is 7" tall and long, and 25"'s long resulting in a tuning of 34hz.

The mono-channel amplifier's LPF knob is only marked at its beginning(35hz) and end (250hz). We'll want to set the LPF at around 80hz so that the subwoofer does not attempt to play any notes higher than 80hz. Since the knob is unmarked, we will guesstimate and use a little math to adjust it.

Such as:

250 - 35 = 215hz

215hz*1/4(Or also .25) = 53.75hz

Now lets add 35hz to that value and we have:

88.75hz, That is slightly higher than our target value so we'll lower the knob ever so slightly below 1/4 of its turning range. And guesstimate that we're in the lower 80's or higher 70's area.

Now that we have the LPF set to a optimal frequency, it is time to set the Sub-sonic filter also to a frequency. The sub sonic filter disallows the subwoofer to play below its given frequency. Its knob is also unmarked in incremental values so we must use a little bit of math here as well.

The SSF knob on the Hifonics 1606d begins at 15hz and ends at 35hz. A good frequency for this would probably be 25hz so that the subwoofer does not play any note below 25hz which could result in bottoming out and may also damage the subwoofer.

We'll also be using math here as well, but no guesstimating.

35 - 15 = 20hz

20hz*1/2 = 10hz

10hz + 15hz = 25hz

So according to the above, to reach our target value, all we have to do is set the knob to the 12'o clock position. Since the sub woofer is behind the seat, there is no need for a phase adjustment. And the goal to getting a good, loud, and unclipped signal will mean that the remote bass boost and amplifier bass boost remain untouched throughout this process.

Also setting the gains will be our next process.

Next up we have the Sundown SAX 100.2 two channel amplifier which is rated at 100x2 @ 4-ohms, slightly underrated so close to 125x2 @ 4-ohms. This amplifier is powering the Rainbow SLC component set which takes around 100 wrms; 150 wrms maximum.

There are three switches on the amplifier, LPF, Full, and HPF.

Since the two channel amplifier is powering the front stage and the front stage only, we will be using the HPF, which will render the LPF knob on the amplifier useless. The HPF knob, as with the Hifonics LPF knob has unmarked increments aswell, so will be using some mathematics and guesstimating to sort out the HPF here.

The beginning and end values are 50hz and 500hz.

500-50 = 450hz of range.

We're looking at the amplifier picking up the note range where the amplifiers have left off. Thus we're looking in the 80-90ish range. Around 85hz. We dont want the midbass and subwoofer playing the same notes, because either the subwoofers will struggle to hit the highs, or the midbass will struggle to hit that low.

Basically since 50hz is extremely close to this value and a 35hz rise is very little given the range, we'll just barely turn the HPF knob above 50hz. But realistically we're looking at moving it around 1/12's of the way around.

As with the other amplifier, the bass boost will be untouched, so will the LPF, and also will the sensitivity for now.

With these settings set, the speakers should be doing the following.

The subwoofers should have a playing range of 25hz - 80ish hz.

The component set should have a playing range of 85hz - Max Tweeter freq.

Now to correspond these figures with the settings on the head unit and we'll begin to work on the gains.

The x991 has a crossover feature which allows you to choose and manipulate a playing range for your front, rear, and subwoofers. But we're only working with the front and subs.

he cross over allows you to choose the octave and and intensity of the slope, the slope determines the falloff in volume per octave above and below the determined octave.

We will set this accordingly to our amplifier settings.

The subwoofer will be set with the phase normal, the playing frequency will be 60hz with a slope of -12db. This allows the subwoofer to play with the approx. volume until the amplifier's LPF cuts it off.

The front midbass will be set with the following, 80hz with a -18db slope, to quickly eliminate any possible notes which may have not be accounted for below the supposed 85hz HPF setting.

Now there are a ton of features on the x991 but we won't get to them until later.

Now we will begin to to set our gains. FUN!

Now the input sensitivity/level/gain etc has different labels on each amplifier. The Hifonics, it is called the level and it ranges from 0.2v to 9v, pretty understandable. The sundown it is labeled sensitivity and ranged from Min to Max.

To determine the proper gains setting we're going to use the target voltage equation of:

sqrt(watts*ohms)

So according to this equation, the Sundown amplifier is rated at:

sqrt(100*4) = 20 AC Volts

And the Hifonics is rated at:

sqrt(1600*1) = 40 AC Volts

But due to the overratedness of this amplifier, achieving that voltage could mean a higher THD or distortion percentage of value so we'll aim for something less.

sqrt(1200*1) = 34.6 AC Volts

Now to achieve this, we'll first disconnect the speaker terminals to both amplifiers and we'll switch the source to CD and insert out test tone CD. Now doing this procedure will require us to do alot of monitoring. The goal of the game is to play a tone in the optimal range of the amplifier which we're setting the gains and then adjusting the gains to meet the target voltage.

First the Hifonics amplifier, this is a pretty important step because we want to get the subwoofers to play their smoothest and loudest at all possible octaves with barely if any clipping.

We'll be playing a test tone. Also for this procedure, all setting besides the HU x'over settings will be flatlined. That includes Loudness, and any volume offset. But we will also max out the subwoofer setting, this allows for maximum voltage through to the RCA pre-outs and also makes reaching that target voltage easier to achieve.

The optimal test tone given our frequency range of the subwoofer and settings on the HU and amplifier will be 50hz. Or the test tone I am playing will be 50-59hz. If needed, we may dip down to the 40hz octave.

The optimal test tone given our frequency range of the component set and settings on the HU and amplifier will be 90hz or even 100hz. We'll dip in both ranges.

With the gains properly set, there should be no need for bass boost, bass eq, different volume increasing or offsetting values on the HU. Setting these may/will clip your speakers and result in distortion that sounds plain awful and not very impressive. But if you feel the complete need to adjust these settings, do it very carefully as to not damage your equipment.

Click to read more...

 

[Trepkos 10+ year member]

Here is where I run into problem number 1: Regarding the hifonics amplifier. With all settings turned down as they properly should I have atleast 34ish voltage. But with the LPF set at 1/3 of the way, this is how the AC voltage increases and drops from a range of 10hz to 119hz. To get any voltage close to where it needed to be in the 50hz - 59hz range, I had to set the LPF to 1/3 of its total turning range.

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I have to turn the gains on the amplifier as their maximum to achieve this following range. Subwoofer input at +15/15 on the HU.

10-19hz = 7.1 - 17.2 AC V(Question number 1: Why would there be any voltage whatsoever when the SSF is set at 25hz? Also notice the drastic change in voltage.

20-29hz = 18.3 - 35.2 AC V(Same question as above.)

30-39hz = 36.3 - 37.3(This octave seemed to be where the amplifier's peaked in its power output, 37.3v = 1400watts!)

40-49hz = 37.1 - 33(Drastic change here also)

50-59hz = 32.3 - 25.3

60-69hz = 24.2 - 17.1

70-79hz= 15.3 - 10.3

80-90hz = 10.0 - 5.9

90 - 99hz = 5.6 - 3.3

100 - 109hz - 3.1 - 1.8

110 - 119hZ - 1.7 - 0.0

------------------------------------------

The problems here are the following: Gains are at maximum, and the pre-outs on the HU are rated at 5volts and the SW input is at +15 on the HU.

-------------------------------------------

The sundown gains tuning went a whole lots smoother. Though the HPF didn't stop voltage from leaking in ranges lower than what the HPF was set at. Gains are just a tad over 1/2.

This test went from a range of 10hz to 169hz

10-19hz = 0.0 - 0.2

20-29hz = 0.3 - 1.8

30-39hz = 2.0 - 2.4

40-49hz = 2.6 - 3.5

50-59hz = 3.7 - 6.7

60-69hz = 6.8 - 11.4

70-79hz = 12 - 16.1

80-89hz = 16.2 - 19.8

90 - 99hz = 19.8 - 22.5

100 - 109hz = 23.9 - 26

110 - 119 = 26 - 27.2

120 - 129 = 27.3 - 27.8

130 - 139 = 28 - 28.3

140 - 149 = 28.4 - 28.3(It seemed that 130 - 150 was the peak output range).

150 - 159 =28.3 - 28.2

160 - 169 = 28.1 - 27(And from this point onwards the voltage dropped down once again.)

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So from the above statistics, does this mean that the peak range or frequency that I should be setting my gains for the subwoofer is 30-39hz.

And the peak range of frequency that the two channel amplifier plays at is 140-19hz. So to set my accurately as possible I should set the gains so that the amplifiers peak at their target voltage or very close to it?

My other question is: Why is there any voltage at all coming from the amplifiers in areas that are deadlisted by the filters on the amplifier? Should the subwoofers be 0.0 AC volts in the 10 - 24hz range, and the 80hz+ range?

Shouldn't the component set be 0.0 from 10hz to 85hz?

More questions to come and to be answered, but at the moment it is 1am and Im about to call it a day. There is a whole lot more, but at the moment, just help me figure my way through this part.

 

[Rashaddd 5,000+ posts]

 

10-19hz = 7.1 - 17.2 AC V(Question number 1: Why would there be any voltage whatsoever when the SSF is set at 25hz? Also notice the drastic change in voltage.

20-29hz = 18.3 - 35.2 AC V(Same question as above.)

30-39hz = 36.3 - 37.3(This octave seemed to be where the amplifier's peaked in its power output, 37.3v = 1400watts!)

40-49hz = 37.1 - 33(Drastic change here also)

50-59hz = 32.3 - 25.3

60-69hz = 24.2 - 17.1

70-79hz= 15.3 - 10.3

80-90hz = 10.0 - 5.9

90 - 99hz = 5.6 - 3.3

100 - 109hz - 3.1 - 1.8

110 - 119hZ - 1.7 - 0.0

 

 

A sub sonic filter (LPF/HPF) doesn't just cut off the power below a certain frequency, but rather decays it over a certain period of frequencies. For example, if this is a 24db filter, (which it should be on an amp in order to avoid phase shifting) 1 octave below the subsonic filter will be -24db's from what it normally would be without the filter. make sense?

 

[PaulD 10+ year member]

a couple of comments ..

First of all, potentiometers (like gain, sensitivity, freq, etc ..) are not necessarily linear, many work on a logarithmic scale. So you can't always say that if the sens range is 1 - 5 volts then the center position is = 5+1/2 or 3 volts

Secondly, a filter is NOT a brickwall. Many amps have a built-in crossover of 12 or 18 db/octave. Each 6 dB is a halving (or doubling) of voltage and each octave is is a halving or doubling of the freq. For example a note of 40 Hz - one octave up is 80 Hz (which is also the same note on the musical scale, just one higher). So if you're HPF on your sundown is set to 80 Hz at 12 dB/oct and you are seeing 20 volts above 90 Hz then at 40 Hz (which is one octave lower than the crossover point) the voltage will be a mulitple of 1/2 for each 6 dB the crossover is.

so for a 80 Hz HPF freq and 20 volts of output (above 90 Hz or so, which is in the pass band) expect the following results.

90 Hz voltage = 20 volts

80 Hz voltage = -3 dB

voltages at 40 Hz:

6 dB/oct = 1/2 * 20 = 10 volts

12 dB/oct = 1/2 * 1/2 * 20 = 5 volts

18 dB/oct = 1/2 * 1/2 * 1/2 = 2.5 volts

 

[mlstrass 5,000+ posts]

If your HU has the xovers you need I would use those vs the knobs on the amps as they're not linear/accurate like you're thinking....

 

[Trepkos 10+ year member]

Ok, definitely the information I'm needing. But a few more questions before I begin working on this again.

Does this range of playing seem ideal for the system?

Subwoofer

10-19hz = 7.1 - 17.2 AC V

20-29hz = 18.3 - 35.2 AC V

30-39hz = 36.3 - 37.3

40-49hz = 37.1 - 33

50-59hz = 32.3 - 25.3

60-69hz = 24.2 - 17.1

70-79hz= 15.3 - 10.3

80-90hz = 10.0 - 5.9

90 - 99hz = 5.6 - 3.3

100 - 109hz - 3.1 - 1.8

110 - 119hZ - 1.7 - 0.0

With the sub woofer output peaking at 37.3 at the 30-39hz range is pretty much ideal because the box is tuned at 34hz. But should the LPF filter be adjusted lower so that the slope is raised in intensity and regions above 80-90 do not see much power if any at all?

Also since the voltage peaks at the 30-39hz range, should this be the range I should test the amplifier at when setting the gains?

Component Set

10-19hz = 0.0 - 0.2

20-29hz = 0.3 - 1.8

30-39hz = 2.0 - 2.4

40-49hz = 2.6 - 3.5

50-59hz = 3.7 - 6.7

60-69hz = 6.8 - 11.4

70-79hz = 12 - 16.1

80-89hz = 16.2 - 19.8

90 - 99hz = 19.8 - 22.5

100 - 109hz = 23.9 - 26

110 - 119 = 26 - 27.2

120 - 129 = 27.3 - 27.8

130 - 139 = 28 - 28.3

140 - 149 = 28.4 - 28.3

150 - 159 =28.3 - 28.2

160 - 169 = 28.1 - 27

This looks pretty good but could the HPF we adjusted for a sharper slope so theres no voltage above 10 in the 70hz and lower range, or would this affect the amount of power in the 80+ range as well. And same question as above, should I use the 130-159 area for reference when setting my gains since it is the peak area?

And last but not least question:

To completely take the LPF and HPF control off of the amplifiers and leave it up to the crossover control on he HU would mean doing the following?

Setting the SSF at 15hz and LPF at 250hz on the subwoofer amplifier.

Leaving the HPF switched on at the Sundown amplifier but move it all the way to 500hz.

And set the HU crossovers to about.

Subwoofer - 60hz with a -12 db/octave

Component set - 80hz with a -18db/octave

 

[BEAVER.989 10+ year member]

Mathmetical equations, charts, graphs, numbers and measurements are great... But the real question is "How does it sound?".

This is all that really matters in the end.

 

[Trepkos 10+ year member]

Mathmetical equations, charts, graphs, numbers and measurements are great... But the real question is "How does it sound?".
This is all that really matters in the end.

Well, we're using mathematical equations, charts, graphs, numbers, and measurements to try and determine technically how to get the best, most optimal performance out of the system.

 

[Trepkos 10+ year member]

Any more comments?

 

[Trepkos 10+ year member]

Ok, continuing setting the gains I decided to keep to my playing range on both sets of speakers. I set the gains accordingly to their peaked playing frequencies.

30-39hz for the subwoofers.

130 - 300+hz for the component set.

I have finished setting the gains for the sundown amplifier, whose target voltage is 20volts. I came to 22volts, the amplifier maxes it output at around 22.3volts and stays steady from 130hz to 300hz with no increase or decrease in voltage from that range.

With the gains maxed out on the Hifonics amplifier I am getting around 38volts at its peak output range(30-39hz). I am going to drop the gains a bit to get a steady 34.6 or so volts for around 1200watts being sent to the subwoofer at its maximum output.

With turning the gains just a tad below their maximum I was able to achieve the exact voltage of 34.6volts which steadily increased and decreased with each range above or below that 30-39hz testing range.

So as of now, my system should be the following:

Subwoofer + Amplifier

Peak Output: 34.6volts = 1200watts

Peak Range: 30-39hz

Total Audible Range: 25hz - 80hz(Given the theory that 100watts RMS would not be able to move the subwoofer significantly enough to make any audible sound.)

All Loudness/Volume Offset/Bass EQ/Boost have been shut off.

*Due to the above, clipping should be a minimum and the subwoofer should get its most power in the range in which the box it is sitting in was tuned.

Component Set + Amplifier

Peak Output: 22.4volts = 125watts

Peak Range: 130hz+

Total Audible Range: 85hz+(Given the theory that 25watts RMS would not be audible enough through the component set.)

*Same as the above, plus crossovers are still at default.

Everything seems to be set now.

 

[Trepkos 10+ year member]

Ok, where I decided to play some music and show you guys what exactly it all sounds like with all volume enhancing and bass boost options flatlined or at their minimum and the gains properly set via a DMM and test tones at their peak frequency with their frequency ranges also set.

This footage was taken with a camcorder so it will probably be higher quality then the usual cellphone and digicam vids. I decided to do my testing with some of the usual hip hop heavy hitting songs.

http://s286.photobucket.com/albums/ll101/Trepkos01/?action=view&current=bastest.flv

The problem you can see here is despite the ways the gain has been set, it seems that the subwoofer is not being pushed hard enough to really reproduce the notes with as much intensity that you usually see in other videos with the Fi Q 15".

Also, the midbass can not play the notes that it is trying to as you can hear at the end of the video which means I may need to set the LPF or HU crossover a tad bit higher.

So why is my sub woofer barely moving and playing?

 

[BEAVER.989 10+ year member]

Ok, where I decided to play some music and show you guys what exactly it all sounds like with all volume enhancing and bass boost options flatlined or at their minimum and the gains properly set via a DMM and test tones at their peak frequency with their frequency ranges also set.
This footage was taken with a camcorder so it will probably be higher quality then the usual cellphone and digicam vids. I decided to do my testing with some of the usual hip hop heavy hitting songs.

http://s286.photobucket.com/albums/ll101/Trepkos01/?action=view&current=bastest.flv

The problem you can see here is despite the ways the gain has been set, it seems that the subwoofer is not being pushed hard enough to really reproduce the notes with as much intensity that you usually see in other videos with the Fi Q 15".

Also, the midbass can not play the notes that it is trying to as you can hear at the end of the video which means I may need to set the LPF or HU crossover a tad bit higher.

So why is my sub woofer barely moving and playing?

It's not despite of it, it's because of it. Music never appraoches the volume level of a pure tone. This is why setting gains with a dmm is useless. Use your ears, they're the best tools you own.

 

[WrenchGuy 10+ year member]

Well music and test tones are of different sorts.

I usually use the DMM as a reference in just knowing that theoretically its making certain power with test tones.

Then I go by ear on familiar music with a dynamic range of frequencies. Jazz and some Techno usually fair well for me anyway.

You almost always can add more gain after using a DMM. There is a lot of dispute over using a DMM. Hence its only a reference for me.

 

[Trepkos 10+ year member]

Well music and test tones are of different sorts.
I usually use the DMM as a reference in just knowing that theoretically its making certain power with test tones.

Then I go by ear on familiar music with a dynamic range of frequencies. Jazz and some Techno usually fair well for me anyway.

You almost always can add more gain after using a DMM. There is a lot of dispute over using a DMM. Hence its only a reference for me.

Ok, well I maxed out the LPF to 250hz, the SSF to 15hz and on the Sundown amplifier I maxed out the HPF at 500hz and I am letting the HU crossovers do most of the work.

The SW crossover is set at 60hz with a -12db/octave, which means that at 120hz the subwoofer plays at -18db then its volume at 60hz, and at 30hz the subwoofer plays at -18db then its volume at 60hz.

The component set is similar as to which it is -18db/octave and set at 80hz. I noticed two things were fixed by doing this.

The midbass no longer bottoms out on the same song at the end of that video, there is a distinct volume increase out of the subwoofer, yet nothing impressive. Next I am going to play with the gains the bit to see how far and loud I can take the system without too much clipping, unfortunately the gains on the Hifonics amplifier is almost at its max so not much head room there. The sundown amplifier leaves a lot of room for option though.

I will take a video and see what you guys think when Im done doing this.

 

[microhaxo 10+ year member]

dude, you are going way too far with what you want to do..

follow this:

set bass boost to zero,

LPF at 80 or 100

download a -3db 50hz test tone

unhook the wires going to the sub and hook up the dmm to them

play the -3db 50hz test tone at listening volume and turn the gain up until you see 32 volts on the dmm

turn off car, re hook up wires and proceed to enjoy music.

If the amp doesnt output 32v by its self with gain then turn up the sub output on the hu till you reach 32v, do not mess with bass boost.

Also, every song is different. That song by young jeezy put on with kanye outputs my exact rms voltage needed for a few bass hits, but my kanye graduation cd outputs at most only 280w rms with my setup.

but it still hits hard and sounds great.