| Author | Subject: Ports? |
| Ed | Posted At 13:23:55 06/03/2001
Does it matter which side you put the port on based on where the sub is located. Does it even make a difference? |
| Amos Chipotle |
Re: Ports? (Currently 0 replies)
Posted At 23:45:08 06/03/2001 Whats a port asshole? |
| Ed |
Re: Ports? (Currently 0 replies)
Posted At 01:07:15 06/04/2001 Not for the deathbox. But for just a "vented" or "ported" box. |
| Doc |
Re: Ports? (Currently 0 replies)
Posted At 03:27:19 06/04/2001 Ed, dont mind "chip," please ignore. It is usually best to port it on the same side. This is because of a term called phase. If you toss a port on a side that the speaker doesn't fire out of then it will take some time for the port to catch up with the woofer and vice versa. See a ported box uses the woofer above its tuning freqency and during the tuning frequency the port takes over leaving the speaker motionless. So in actuallity the port and woofer trade places at different frequencies. Above the tun freq the woofer is the most prevelant source of sound and at the tun freq the port becomes the loud aspect. This is why its a good idea to have them on the same side. You want to keep the two working together. Locating it on another side will yield a time delay during the shift between woofer and port, thus making things sound extremely muddy since it takes the energy from both to converge and be one. Transient response will be lost at the very least. Its also a good idea to put the port close to the woofer to decrease the time delay between the two. |
| Ed |
Re: Ports? (Currently 0 replies)
Posted At 11:37:35 06/04/2001 What about in a bandpass box though? |
| Mann |
Re: Ports? (Currently 0 replies)
Posted At 22:22:07 06/04/2001 Yes. There are many different bandpass and ported designs that locate the subwoofer either on the left, right, center, bottom, top, and back of the box. Just like the sub, the port needs to be located in best possible location dependent upon the application. Not only is port location important, but port length and size is also. As Doc has stated, the port should come out of the front if you want maximum "punch" so that the air coming out of the port is matched to come out at the same time as the cone near the port tuning frequency (in phase). But, dependent upon the application, the port should come out of the back, opposite side of the cone, (usually in home loudspeakers because the sound will utilize the wall to disperse (direct reflecting) and still match the cone frequency near the port tuned frequency). Bose is well known for using this as their selling point, but most of us consider this to create some pretty major coloration of the music, not reproducing true representation of the music. Some sub ports face down, back, or up, (usually in home subs because the sound will fill the room by being omnidirectional anyway). Some car subs need the ports facing the back, sides, or corners of the vehicle to create the most "cabin gain" as possible. But it takes a very knowledgable builder to recognize the best possible solution. Doc, I don't understand what you mean by the speaker being motionless at the tuned port frequency. Could you elaborate? I am curious. |
| Doc |
Re: Ports? (Currently 0 replies)
Posted At 00:13:54 06/05/2001 Well, it moves a little at the port frequency, but this is where the port takes over with the load of reproducing the soundwaves, in doing so the speaker becomes almost motionless. Whereas other frequencies it may move quite a bit outside the tuning frequency. |