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Port noise?

Old 12-13-2017, 10:44 PM
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Port noise?

Hello there my fellow sound reproduction enthusiasts. So I've only been at this a short time. When I was younger I had played around with some pretty simple set ups. So I knew the basics. I've had a couple nice head units I've also done the add a sub to a factory system thing. I remember back in the day I had to have a crossover network because amps didn't really come with it built in. Never heard of a subsonic filter till recently... you get the point. So here's my story so far. I've got a accord coupe. Kept the factory nav. And added a Kenwood head unit under the factory stuff inside the pocket. Nice idea really. Got some 6.5 polk speakers for tghe doors. Made a adapter. Pretty clean install. Ran new 12 gauge ofc wiring to them. That was fun. It comes from the 4 channel amp in the trunk. Replaced the factory 6x9s with some 150 watt rms Jensen dub editions. They went on sale. Not a perfect fit had to use the grills instead of the Honda's factory ones. Looks cool tho. I'm not going to talk to much about the 4 channel feeding the mids and highs. It does a nice job but its a brand everyone will laugh at. There is a good reason I choose it. Returning it would be so easy I gave it a chance. Anyways so now for the fun part. It all started because I was given a sealed box with two 12 inch majestic subs and a pioneer 900 watt amp. All of which work. The box is home made. Pretty nice carpeted and all. Got 2 caps to go along with it but I don't really believe in using them. So the first thing i did was pull the subs. Bought some massive audio tko 124s and realized the subs need a different amp. Amp shopping on a tight budget was real fun. Found a planet audio amp cheap on the web. I could do a 4 ohm or 1 ohm configuration with the subs so I decided I'd do a 4 ohm. Buy ask amp that would do what I wanted and in the future upgrade subs and run a 1 ohm. I took a chance on the budget amp and it did not pay off. Tested that amp at work where I have meters and amp clamp and scopes... not pleased at all with planet audio. So shopping again stumbled onto Rockville. Got a db 15 6000 watt blah blah blah and low and behold it's also cea rated. And rms. And max... lol comes with a nifty birth certificate... They are all the same except the serial number changes... lol gotta love marketing schemes. Anyways long story short it's a good amp. Tested good does what it says cea ratings anyways. That's all I care about. Next I heard from massive that there subs perform better in a ported box. Shopping again found a slightly used box loaded with some Kenwood excelons for cheap. Put the massives in wired em wrong. Sounded as loud as the sealed box. Wired em correct. They bang real good. Cool... then I get a hair or an itch or whatever you call it and I decide I want to double my power. Shopping again. Thought I found 2 subs a box and an amp for cheap. Drive an hour find out the subs are shallow... not gonna work out. Bought the amp tho. Nice jbl crown amp. Found 2 new subs from my buddy who also made my install kit. All ofc monster cable and rockford speaker wire. Decided id build a seperated chamber box for the new massive gtx 124 subs and use the new amp along with the rockville to run em. Somewhere along the line i talked myself into having matching amps so I bought another Rockville. Here's the trouble. My box turned out to be a nightmare. First off the initial cuts at home depot were wrong. So I had to re map the lay out. What I wanted to do is a double baffle front. 3/4 mdf dual slot port separate chamber box. Sounds easy right? Well I ended up with a double baffle front 3/4 skinny slot ported ???? Wtf the dimensions came up a little shorter because of a bad cut. And I miss placed my ports. They are only 1.25 inches wide by 12 inches high. That makes a port length of like 10 inches. To get a 40 Hz tune. They should have been twice as wide and 26 inches long. I've got crazy port noise. It did tune to 40. Used the old salt on the woofer and sine wave generator trick. So anyone have a solution for the port noise? I tried rounding the edges with my router already.

Last edited by Fathershelper; 12-13-2017 at 11:08 PM.
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Old 01-09-2018, 11:30 PM
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port noise is caused by bad box designing.... your port velocity is too high

you need to have the port velocity BELOW 10%....... I usually stay between 5% to 8%
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Old 01-10-2018, 08:50 AM
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Yeah i scrapped that design. New box has 3 inch wide slot ports. Works perfect.
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Old 01-14-2018, 09:05 PM
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New design. The baffle is the same color as the vehicle.
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