audio set-up for beginners [continued]

**jmpet626** · February 5th, 2017 03:25 PM

Help po mga sirs, I recently replaced my Kinetic KD 800.1 Mono amp to a Category 7 1000.1 mono amp. First time to DIY and when I finished installation, may malakas na whining sound ako na ririnig sa front separates. If I remove the RCA from the Head Unit to the Input of the Mono amp, nawawala yung whining sound.

My previous setup was working fine naman and before I bought the category 7 mono amp, na test namin ng seller and wala whining sound. Napansin ko lang pag On ng ingnition iilaw yung protect LED ng mono amp for about 3 secs then mawawala and i ilaw na yung power LED niya. Is this normal?

Could it be insufficient grounding? I double checked my connections naman and secured it properly.

**armour** · February 5th, 2017 04:02 PM

hi sir markgy, thanks for the advise and answering
sorry i am in the province of MAGUINDANAO i cannot find a good car audio installer he he he he..,
so my route for the subwoofer box will be DIY, more fun and challenge but lack of information
by the way my box dimension L-19"xW-12xD-8" each
I minus all size by 1" since I have a 1/2" of MDF to get my internal dimension which is 1,386 cub. inch and divide by 1,728 to get 0.80 cub. ft.,
I can easily make it to 0.35 cub. ft as recomended by Infinity for sealed enclosure, by putting a wall making my L-19" to L-9", which will give me a appx. 0.35 cub ft.
If my enclosure is thin for 1/2" I can do a double wall which will make it to 1" and re do all the calculation.
But I heard alot of good reviews on PORTED ENCLOSURE, thats why i need help / information on this on how to do this project DIY box
Infinity recomended a 0.65 cub. ft of volume for ported subwoofer box they give a size of port opening of 2.5" but the depth is 8- 13/16", and my box is internal is only 7" and my speaker depth is 5-3/16" can i do the depth of port to 4.5", would it do any bad effect on the sound quality of subwoofer.
Is there anything I can do make a ported enclosure or I will stick to sealed na lang.

**nixce** · February 5th, 2017 06:56 PM

Originally Posted by armour

hi sir markgy, thanks for the advise and answering
sorry i am in the province of MAGUINDANAO i cannot find a good car audio installer he he he he..,
so my route for the subwoofer box will be DIY, more fun and challenge but lack of information
by the way my box dimension L-19"xW-12xD-8" each
I minus all size by 1" since I have a 1/2" of MDF to get my internal dimension which is 1,386 cub. inch and divide by 1,728 to get 0.80 cub. ft.,
I can easily make it to 0.35 cub. ft as recomended by Infinity for sealed enclosure, by putting a wall making my L-19" to L-9", which will give me a appx. 0.35 cub ft.
If my enclosure is thin for 1/2" I can do a double wall which will make it to 1" and re do all the calculation.
But I heard alot of good reviews on PORTED ENCLOSURE, thats why i need help / information on this on how to do this project DIY box
Infinity recomended a 0.65 cub. ft of volume for ported subwoofer box they give a size of port opening of 2.5" but the depth is 8- 13/16", and my box is internal is only 7" and my speaker depth is 5-3/16" can i do the depth of port to 4.5", would it do any bad effect on the sound quality of subwoofer.
Is there anything I can do make a ported enclosure or I will stick to sealed na lang.

Hi sir,, in my own opinion, sealed box is better. More accurate, hindi delayed ang bass, tight, swabe pero wag mag expect ng gumagapang na bass. Anyway, yung infinity subs m, pang SQ naman, so masarap yan bumayo sa sealed box. Hehe malambot. Tama ba ako? Naka sealed box yung infinity subs namin, kaya nasasabi ko yan. 12". Pero sa RnB na music, ok padin naman,, hindi masakit sa dibdib.

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**markygy** · February 5th, 2017 07:17 PM

Originally Posted by armour

hi sir markgy, thanks for the advise and answering
sorry i am in the province of MAGUINDANAO i cannot find a good car audio installer he he he he..,
so my route for the subwoofer box will be DIY, more fun and challenge but lack of information
by the way my box dimension L-19"xW-12xD-8" each
I minus all size by 1" since I have a 1/2" of MDF to get my internal dimension which is 1,386 cub. inch and divide by 1,728 to get 0.80 cub. ft.,
I can easily make it to 0.35 cub. ft as recomended by Infinity for sealed enclosure, by putting a wall making my L-19" to L-9", which will give me a appx. 0.35 cub ft.
If my enclosure is thin for 1/2" I can do a double wall which will make it to 1" and re do all the calculation.
But I heard alot of good reviews on PORTED ENCLOSURE, thats why i need help / information on this on how to do this project DIY box
Infinity recomended a 0.65 cub. ft of volume for ported subwoofer box they give a size of port opening of 2.5" but the depth is 8- 13/16", and my box is internal is only 7" and my speaker depth is 5-3/16" can i do the depth of port to 4.5", would it do any bad effect on the sound quality of subwoofer.
Is there anything I can do make a ported enclosure or I will stick to sealed na lang.

Oh tama pala ang computation mo for the sealed enclosure. I forgot I did enter .5 for the wood thickness.
Sorry about that!

Anyway, maybe this would help..

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**armour** · February 6th, 2017 11:19 AM

* sir NIXCE, thanks for sharing youre experience / info on infinity sub woofer, by the ano dimension o size ng sealed enclosure mo? (L x W x H) para may idea ako about sa gagawin ko, I already purchase 2x8" Infinity sub.
ang alam ko tayo ang masarap bumayo he he he he he he...

* sir MARKGY, thanks for answering ang giving some inputs on subwoofer enclosure, by the way ano gamit mo na software?
Yun binigay mo na info about RE L- Ported Speaker Box Calculator mukhang pasok ako dun sa design nila at mukhang madali gawin.
RE AUDIO - Box Calculator
now I can order my power tools for my DIY project

**armour** · February 6th, 2017 03:59 PM

is it possible to have 1" of L ported sub woofer box and tuned to 42hz?

**jhnkvn** · February 13th, 2017 05:28 PM

Originally Posted by jmpet626

Help po mga sirs, I recently replaced my Kinetic KD 800.1 Mono amp to a Category 7 1000.1 mono amp. First time to DIY and when I finished installation, may malakas na whining sound ako na ririnig sa front separates. If I remove the RCA from the Head Unit to the Input of the Mono amp, nawawala yung whining sound.

My previous setup was working fine naman and before I bought the category 7 mono amp, na test namin ng seller and wala whining sound. Napansin ko lang pag On ng ingnition iilaw yung protect LED ng mono amp for about 3 secs then mawawala and i ilaw na yung power LED niya. Is this normal?

Could it be insufficient grounding? I double checked my connections naman and secured it properly.

Yes. It's a wiring problem so you're picking up the whine. Sadly, correcting the problem takes time. Double check the connections as a start then rewire it.

**jhnkvn** · February 13th, 2017 05:45 PM

Originally Posted by aprilboyidol

kapag 100w rms amplifier ibig sabihin ba 100w sya kapag naka max yung gain

Incorrect. Gain is NOT wattage. It is used to attenuate the signal more than anything. This widespread belief that "gain = wattage" is why people start blowing up their speakers and amplifiers.

For those who wants to understand the concept of the gain knob on your amplifier, do read this link: Amplifier Gain Controls
- this fully explains what it does and the concepts behind it
- way better than me typing out another wall-of-text paragraph

**jhnkvn** · February 13th, 2017 06:08 PM

Re: Ported versus Sealed

Personally, I prefer ported enclosures.

Both concepts have their own pros and cons. For example, technically, sealed boxes will always have higher distortion than ported boxes for a given output while ported boxes will always have time-delay related issues.
- a sealed box is not "SQ" compared to a ported box. That's like saying a Php160,000 JL Fantom 15" subwoofer is not "SQ" because it's ported.
- the time delay concept is one of the reasons why people suck at tuning ported enclosures. However, it isn't night and day difference and that problem is only applicable to the hardcore 1%.

All those misnomers people throw "tightness", "loose", etc. are all analogies that refer to an improperly tuned SYSTEM. It is because people fail to tune their midbass to integrate seamlessly with their subwoofer that you get sloppiness. It's not because of your box.
- I mean, I'm typing this in front of a Dynaudio Excite X12 loudspeaker and it's singing with a port. So is my computer setup with the Klipsch R-15PMs which also has a port.

The reason why people in "SQ" prefers sealed is because it's easier to get it right. However, I've sat in cars with beautifully tuned ported enclosures and it has its own fair share of WOW moments (for example, Mike's Php1.3M full bewith system incorporates a 8" bewith subwoofer in a ported enclosure; so is their midbass ALSO on a ported enclosure).

**jmpet626** · February 13th, 2017 07:08 PM

Originally Posted by jhnkvn

Yes. It's a wiring problem so you're picking up the whine. Sadly, correcting the problem takes time. Double check the connections as a start then rewire it.

Was able to solve the whining noise by adding a ground loop isolatro between the RCA output of the HU and RCA input of the mono amp.