I slapped together a ported box to use a 8" sub I had kicking around. The box is about 9 x 9.5 x 33" and has the driver on one side and a flared 3" port (6.5" long) on the other. A Kicker DX250.1 is powering it. At 4 ohms it's only rated at 140w. At 8 ohm it's even less but it shakes the car like a pair of 12s are back there. 
My question is... How would adding a second identical driver effect the tuning and the sound quality? I know to account for the displacement of the additional driver and may have to adjust the port length. I think now it's tuned to 44hz and plays clearly down to 25~30 with a sweep I found on Youtube. It sounds incredible and I wouldn't want to ruin that but being able to parallel two subs to get 4 ohms might give me a little more output out of it. It's that, or gamble on replacing the current driver with a DVC.
My question is... How would adding a second identical driver effect the tuning and the sound quality? I know to account for the displacement of the additional driver and may have to adjust the port length. I think now it's tuned to 44hz and plays clearly down to 25~30 with a sweep I found on Youtube. It sounds incredible and I wouldn't want to ruin that but being able to parallel two subs to get 4 ohms might give me a little more output out of it. It's that, or gamble on replacing the current driver with a DVC.
Attachments
Bridge the amp, it will see the speaker as 4 ohms.
Running two or more woofers in the same undivided enclosure will affect the way it operates. It will cause over excursion and distortion and will change the Q since the box is set up for one speaker and the size of the box is based on the parameters of the speaker.
If you want to add more woofers then build a new box with separate chambers.
Running two or more woofers in the same undivided enclosure will affect the way it operates. It will cause over excursion and distortion and will change the Q since the box is set up for one speaker and the size of the box is based on the parameters of the speaker.
If you want to add more woofers then build a new box with separate chambers.
I have no idea what the ts parameters are for this driver. I just built a box sized to fit the car and tuned the port for 44hz. I wasn't expecting much and was blown away when it sounded as good as it did. I couldn't be happier with how it turned out so maybe I shouldn't mess with it.
Wouldn't 2 small speakers in parallel just act like a single larger speaker?
It's a single channel class-d amp.
Wouldn't 2 small speakers in parallel just act like a single larger speaker?
It's a single channel class-d amp.
Last edited:
Hi,
2 drivers will act as though they are in half box sizes tuned to 44Hz.
Given your method it may or may not work depending on the drivers.
rgds, sreten.
Changing the driver is a crapshoot. I'd stick with being lucky.
Last edited:
Your probably right there. The port was tuned that high because I listen to a lot of classic rock. I started with 32hz then 38hz but the kick drum was dominating the bass guitar. At 44hz it much better but I was concerned about over-excursion or the system just not being efficient at very low frequencies. Neither of those problems are present in the vehicle. If it works don't fix it?
Right, but at frequencies above or below the tuned frequency the cone will move a lot more. At very low frequencies of say 20~30hz I was worried about over-excursion especially being just an 8" driver. Although it's tuned to 44hz, it easily played (in the vehicle) down to 20hz on a sweep (without distortion or over-excursion). It's roll off seems to start at about 30hz. This is only using my "ear-dyno" but it sounds good to me.
I don't know much about that brand of sub or what bracing and stuffing may be subtracting from the internal demensions of the box but the box may be a little oversized even with it being a ported enclosure. I suspect that it sounds "bigger" since the larger box will extend the low frequency response to a point. The sub was probably designed for a ported enclosure in the first place but I don't know if it is rated for the power going to it.
A sealed, much smaller box (roughly half the size) would increase the power handling and tighten up the bass (less low end).
As mentioned before, one sub per chamber or the subs work against each other dramatically reducing efficiency (in most cases).
A sealed, much smaller box (roughly half the size) would increase the power handling and tighten up the bass (less low end).
As mentioned before, one sub per chamber or the subs work against each other dramatically reducing efficiency (in most cases).
I forgot I had a pair of old 4 ohm MTX 8s in the garage. I tried one in place of the 8 ohm Logitech. It has the same low end responce as the Logi but the kick drum is much tighter and blends a lot better with the bass guitar. It's also a little bit louder. This is what I was looking for when I listen to classic rock but it still didn't have the volume I wanted. The factory system is rated at 300w and the sub was a little weak likely due to the impedance. At 4 ohms my sub amp only does 140 rms. I added the second MTX 8 right next to the first and wired it in parallel. At 2 ohms the amp does 250w rms. This gave me the volume I needed and I didn't notice any change in low end responce but it plays a bit higher then it did before.
In this paticular case, adding another sub to the box didn't damage the performance. It's 1.2 cubic feet in volume so it may be a little more forgiving. If it had ruined my "luck" I'd have rebuilt the same box and just used one driver.
In this paticular case, adding another sub to the box didn't damage the performance. It's 1.2 cubic feet in volume so it may be a little more forgiving. If it had ruined my "luck" I'd have rebuilt the same box and just used one driver.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.