Audio - How to "tighten" up the Bass

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CrealBilly

Jeff
Senior User
Since the factory deck went out in my truck - I've been doing a lot with it's bose sound system. I replaced the deck with a Kenwood 4x 50 watt plus 100 watt sub woofer output and added a 7 band equalizer. It still didn't sound the way I wanted it to - so I started replacing door speakers.

Sounding better but still not what I wanted. So I built two wedge shaped ported sub woofer boxes out of MDF to sit under the rear seat of my pickup. I top loaded them with high power pioneer 10" sub woofers. That was the first major improvement I noticed in sound quality.

But I believe now after much experimenting. Ported boxes make the bass sound muddy and the notes sound slurry to me. My personal music preference is rock and roll and jazz. I went to the home improvements store and bought a length of 3" od internal pipe thread schedule 40 pvc and a plug just because I was curious what a sealed vers / ported boxes would sound like. Much to my surprise the sealed box sounds so much better (tight bass and no slurring notes any more).

A few weeks ago I also installed 2600 watt 6 channel class A/B amplifer under the rear seat and on top of the hump. At the same time I also installed 8" paper cone middle bass woofers and 4" tweeters in both of my back doors. I built 2 two way crossovers for each pair of 8" mid bass woofer and tweeter. When I finally got done and tuned the amp it sounds amazingly clear and is so loud anything over 1/2 way up will run you out of the truck. I can adjust the low bass deep and loud enough that while sitting in drivers seat it will make breathing difficult. It rumbles the back seat and whole cab like crazy and to the point of being stupid. I can sit a beer can on the roof and watch it jump 2" or higher off the roof.

Getting to this point I have aquired a lot of info on how to build you own passive crossovers, speak boxes and how to port tune your boxes. I'm going put 8 more speaker in cab but doing it a little at a time... It's kind of fun designing and building your own car audio system.

When I get everything the way I want it - I'll replace the MDF sub boxes for tone wood curly hard maple.

Not knowing at the time. I went way over board on the 2600 watt 6 channel amp. It's a amplifer designed for a large boat but I put it in the cab of my pickup. I can't get it any higher that 1/2 way up without my ears starting to hurt and my sight becoming blurry. Not to mention mirror s are useless from all the vibration... It's so loud that it's really a health hazard. I need to be very carful or I could go deaf pretty easy if I'm not careful.

Amplifer technology has grown by leaps in few short years. If you look around old school class A/B amps are stilling being made Class A/B is designed for music clarity, newer class D is for power at the sacrifice of clarity. I guess if your into bumpy rap, a Class D and port tuned sub woofer boxes would be better than a class A/B with sealed sub woofer boxes.

It was fun applying my electronics engineering degree that I earned back in the 80' to good use again.
 
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NOTW

Notw
Senior User
I can relate to the breathing difficulties and such from too much bass. When I was younger and thought I was "cool" I had multiple stereos that I built, less for sound quality and more for bass. Everything from (3) 12's to the last stereo I had was (2) Cerwin Vega 15's in a small sedan. Doing everything from building the boxes and wiring them to sound deadening the vehicle, although I did leave the crossover building to a local shop as they had a guru that loved doing it.
 

Mike Davis

Mike
Corporate Member
I built a pair of speakers back in 1980 that were based on the Klipsch horns. The bass port was 79" long, tuned to the lowest note my speaker would reproduce. If the port is shorter than the lowest note then you get all the lower notes piling into that frequency and forming a solid bump also the muddy mix of bass you mentioned. I have seen holes right next to the speaker and called ports, they do nothing but let the speaker rattle. Having no port and a very heavy and insulated box is better than having too short of a port.
 

zapdafish

Steve
Senior User
At first thought you were posting a work out program for Bas. :D

https://www.ncwoodworker.net/forums/member.php?u=1710



Unfortunately for me sound systems are lost on me. If I compare side by side at Best Buy I may be able to tell a difference but but then to me the difference isn't worth double to triple the price. I do like speaker builds tho with fancy veneer. Think someone posted a build several years ago using some wicked looking Burl.
 

The A Train

Adam
User
Porting/venting a speaker or subwoofer enclosure doesnt automatically make a speaker/subwoofer muddy sounding. By adding a port, you are tuning the enclosure. And the diameter and length of the port anlong with the volume of the enclosure tunes it to a different frequency. Think of it like a flute. As the flutest opens and closes the holes, the frequency either raises or lowers.

To make things more complex, each individual speaker/subwoofer has a list of specs associated with it. They will tell you wether one is happier in a sealed or ported enclosure.


Sent from my iPhone using Tapatalk Pro
 

CrealBilly

Jeff
Senior User
Porting/venting a speaker or subwoofer enclosure doesnt automatically make a speaker/subwoofer muddy sounding. By adding a port, you are tuning the enclosure. And the diameter and length of the port anlong with the volume of the enclosure tunes it to a different frequency. Think of it like a flute. As the flutest opens and closes the holes, the frequency either raises or lowers.

To make things more complex, each individual speaker/subwoofer has a list of specs associated with it. They will tell you wether one is happier in a sealed or ported enclosure.


Sent from my iPhone using Tapatalk Pro
Actually the port simulates the same type of effect as blowing across the lid of a pop bottle. The more volume the deeper the frequency. That's why when you blow over the top of a 1/2 full bottle of pop - the note sounded is a higher frequency than a empty pop bottle. Your right about box volume, port diameter and length. But I do not like the sound of a port tuned box to resonte frequency of a speaker. Some say it "adds" to the music - I say it sounds like crap...

To really understand this though you really need a deep dive in T/S (Thiele-Small) parameters of the speaker your working with.
 

Pop Golden

Pop
Corporate Member
Jeff, The standard material for speaker cabinets is MDF. It's use because of its density. The wood part is most of the time veneer. As for style of design, I prefer a folded horn for squeezing the bass out of a speaker. I have designed and built speaker cabinets many time over my wood working time. If you want to see the ultimate speaker have a look at the JBL "Paragon"

Pop

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nn4jw

Jim
Senior User
All this effort to tune speakers. And then you add road noise, tire noise, engine noise, the car beside yours blasting his music and all the rest of it. I really don't get it.
 
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