Subwoofer Mount/Seal in Sealed Box

[djtech2k 10+ year member]

I just bought (2) Sundown SD-2 8" and am putting them in small sealed boxes. I noticed the woofers do NOT have any kind of foam stripping around the surround/mount area so I am concerned about having leaks between the sub and the box. My box is going to be vinyl covered.

Should I put weather stripping around the sub or maybe silicone to seal any potential leaks? Or is that not a concern anymore?

Click to read more...

 

[Jeffdachef 5,000+ posts]

I just bought (2) Sundown SD-2 8" and am putting them in small sealed boxes. I noticed the woofers do NOT have any kind of foam stripping around the surround/mount area so I am concerned about having leaks between the sub and the box. My box is going to be vinyl covered.
Should I put weather stripping around the sub or maybe silicone to seal any potential leaks? Or is that not a concern anymore?

not a concern.

 

[joinaunion]

Are you talking about the rubber ring that the screws will go through?

 

[djtech2k 10+ year member]

So I have the polk component set installed and I setup the amp today. I will post pics.

I followed this article to do the right kind of tuning on the gains and such on the amp. How to Adjust Amplifier Gains Using a Digital Multi-Meter | Learning Center | Sonic Electronix

I could not get this to work or make sense. I followed it closely, but I could never get the voltage to read anything like what it said to expect, even with the gains all the way up. I am using the SQ 90.4, so I came up with about 38 volts. I could not figure out which switch setting to use on the multi-meter, but I tried them all. Playing the 1000hz loop, even with gain at 100%, I only got about 32 volts max. I even bought a new digital meter and no difference. So I put on some music and turned up the gain until I started to hear distortion, then backed it down a bit. I would say the gain is about 2/3 - 3/4 up. That's with all HU features set to 0 or flat. I just don't have a great deal of confidence that the gain setting is good.

The performance is ok, not what I expected in terms of volume. I really have to turn up the volume to like 28 out of 35 for it to get somewhat loud.

Also on the amp, the HPF frequency is a dial from like 20hz - 5khz. So its hard to know where the crossover is set. I have it where I would guess its about 200-400hz. On the amp, the dial is pointed the the bottom left of the letter "H" on the HPF button label.

The HU has a bunch of sound tuning features like EQ, sub, crossover, etc so I guess I will need to fool with those after I get the sub amp setup.

Any guidance on proper amp/gain tuning? I plan to follow the SQ instructions to tune the 1200 from here Amp Setup Instructions.

Here are some pics from the install thus far.

 

[Jeffdachef 5,000+ posts]

So I have the polk component set installed and I setup the amp today. I will post pics.
I followed this article to do the right kind of tuning on the gains and such on the amp. How to Adjust Amplifier Gains Using a Digital Multi-Meter | Learning Center | Sonic Electronix

I could not get this to work or make sense. I followed it closely, but I could never get the voltage to read anything like what it said to expect, even with the gains all the way up. I am using the SQ 90.4, so I came up with about 38 volts. I could not figure out which switch setting to use on the multi-meter, but I tried them all. Playing the 1000hz loop, even with gain at 100%, I only got about 32 volts max. I even bought a new digital meter and no difference. So I put on some music and turned up the gain until I started to hear distortion, then backed it down a bit. I would say the gain is about 2/3 - 3/4 up. That's with all HU features set to 0 or flat. I just don't have a great deal of confidence that the gain setting is good.

The performance is ok, not what I expected in terms of volume. I really have to turn up the volume to like 28 out of 35 for it to get somewhat loud.

Also on the amp, the HPF frequency is a dial from like 20hz - 5khz. So its hard to know where the crossover is set. I have it where I would guess its about 200-400hz. On the amp, the dial is pointed the the bottom left of the letter "H" on the HPF button label.

The HU has a bunch of sound tuning features like EQ, sub, crossover, etc so I guess I will need to fool with those after I get the sub amp setup.

Any guidance on proper amp/gain tuning? I plan to follow the SQ instructions to tune the 1200 from here Amp Setup Instructions.

Turn off all high pass filters on the amp and use the filters on the head unit. You should have no crossover functions used on the amp unless you are planning on going active. Your HPF could very well be at 1khz and cutting out every frequency 1000 and below thats why you never achieved proper voltage.

On the head unit high pass filter 80hz low pass filter 80hz EQ flat for now, loudness off, bass boost off. What head unit are you using? where did you get your test tone from and what db level is it?

 

[djtech2k 10+ year member]

My HU is Kenwood Excelon KDC-X799.

I saw a HPF mention in the HU, but I need to make sure it will apply to the right RCS outputs. I have Front, Rear, and Sub. Front and Rear outputs are going to my highs amp, but I am only using 2 channels right now.

On the HU is mentions "bands" on the audio control section, so I thought that was the EQ. There is not "off" setting. I chose "user" but everything else is zero or off.

I bought a test tones CD from here: CD Information

Like I said, I tried every switch setting on the MM, but not sure which is right.

The SQ site I posted says to use their "remote" with clipping indicator for the mono amp. Is it reliable?

 

[Jeffdachef 5,000+ posts]

My HU is Kenwood Excelon KDC-X799.
I saw a HPF mention in the HU, but I need to make sure it will apply to the right RCS outputs. I have Front, Rear, and Sub. Front and Rear outputs are going to my highs amp, but I am only using 2 channels right now.

On the HU is mentions "bands" on the audio control section, so I thought that was the EQ. There is not "off" setting. I chose "user" but everything else is zero or off.

I bought a test tones CD from here: CD Information

Like I said, I tried every switch setting on the MM, but not sure which is right.

The SQ site I posted says to use their "remote" with clipping indicator for the mono amp. Is it reliable?

high pass on the head unit should work for front and rear RCAs basically only go to your highs USE IT. Low pass will only work for the subwoofer output.

The indicator is pretty spot on with an oscope.

Out of curiosity whats the wire kit you used to wire the amp with and how is your electricals looking like?

 

[djtech2k 10+ year member]

So you suggest setting the highs amp to full range and set the HU crossover? How about the mono bass amp? Same thing or use the amp crossover? Or Both?

Are you saying the "remote" knob with clip indicator process is a good one to set the mono amp gain?

For wiring, I bought it all separate. I bought 1/0 from battery to the fuse block. From fuse block to amps, I use 4 gauge to each. For ground, I use 4 gauge from amp to ground sport, which is within about 2 feet. I bought a T-Spec battery terminal and T-Spec 2-fuse block. Since the 90.4 amp has 2x40amp fuses in it, I put an 80 amp fuse in the fuse block. I will install the bass amp tomorrow, but it takes 40x3 fuses in the amp so I was planning to use a 120 amp fuse in its spot on the block. Does that sound right? I also bought a main-line breaker and the Big 3 upgrade kit, but haven't installed them yet. Not sure if I need them or not. The breaker is a 200 amp breaker, but again I may or may not use it.

 

[cfox10 10+ year member]

So you suggest setting the highs amp to full range and set the HU crossover? How about the mono bass amp? Same thing or use the amp crossover? Or Both?
Are you saying the "remote" knob with clip indicator process is a good one to set the mono amp gain?

For wiring, I bought it all separate. I bought 1/0 from battery to the fuse block. From fuse block to amps, I use 4 gauge to each. For ground, I use 4 gauge from amp to ground sport, which is within about 2 feet. I bought a T-Spec battery terminal and T-Spec 2-fuse block. Since the 90.4 amp has 2x40amp fuses in it, I put an 80 amp fuse in the fuse block. I will install the bass amp tomorrow, but it takes 40x3 fuses in the amp so I was planning to use a 120 amp fuse in its spot on the block. Does that sound right? I also bought a main-line breaker and the Big 3 upgrade kit, but haven't installed them yet. Not sure if I need them or not. The breaker is a 200 amp breaker, but again I may or may not use it.

Use the headunit for all crossovers - sub, mids/high, etc.

The remote knob with clipping indicator is perfectly fine for setting the amp gain. Use the test tone, set the headunit volume, adjust until clipping, back down some.

As far as the fuses, you should fuse for the wire. It's to protect the vehicle, closer to battery the better. One fuse near the battery that is 200a would be sufficient as it will be equal to the total current draw you should have/not exceed.

 

[Jeffdachef 5,000+ posts]

yup^^^ every crossover piece is done on the head unit. I did say to turn off every piece of crossover on the amps Even on the subwoofer amp and gave you head unit numbers to use to tune to.

 

[djtech2k 10+ year member]

Thanks. I hope to get the rest done today. I will just disable the amp crossovers and do it thru the HU. On the highs amp, I will try the multimeter thing again. Hopefully it will work this time. I am running 90 watts at 4 ohms. I am assuming the result should not be the gain set all the way up.

I don't think my HU HPF has anything below 100 as an option. For the sub, I think 85 is the lowest.

Hopefully I can post more pics this evening.

 

[djtech2k 10+ year member]

More work done today..

I retried the amp tuning with no success. I disabled the crossover on the highs amp. I set it on the HU. All eq set to zero. When I check voltage its either very low or a negative number on the MM. I don't know the right setting to use on the MM, so I just turned the gain up until I heard distortion, which was around 75% up.

The sub amp will not allow you to disable the crossover plus it has a subsonic dial. I followed SQ and set the dials to where I thought it looked like their recommendations. It's just hard with dials and no markings.

On the sub amp I used the clipping indicator on the remote. When bass hits, the light on the remote flashes but it doesn't stay red when there's no bass. The gain is about 2/3 or 3/4. Not sure if its right or not, but with that gain set and turning up the sub setting on the HU and turning on loudness on the HU, it sounds pretty good with just 1 8".

I only have 1 woofer installed because the second has an issue. When trying to mount it, the rubber ring around the outside is not aligned with the screw holes properly. So when I put a screw I to the holes in the rubber, it runs into metal unless I put it at a crazy angle. I could not rotate that rubber ring so I guess I have to send it back.

So I still have some concern about amp tuning but a single 8 sounds pretty good so far.

I'll post a couple pics but nothing a lot new

 

[mfenske 10+ year member]

Assuming your amp is 90 watts at 4 ohms I come up with 18 volts so 33 is WAAAAY higher.

 

[djtech2k 10+ year member]

The way I understood it, it was "Voltage = square root of watts x ohms". So for mine, 90watts, it would be sq. root of 90 is 9.5. 9.5 x 4 ohms = ~37volts. I don't remember what the MM read when I turned the gains up.

 

[comosc]

I think you need to do square root of (90 watts x 4ohms). So square root of 360 which should give you around 18.9 volts.

Sent from my SM-N920P using Tapatalk