Interesting tosay the least.
I can understand all the pitfalls of doing this. At the end of the day, I always read that a ported box is smaller than its equivillent sealed, a ported is louder, thats why evey cheapo megawatt, Matsui, plastic, all in one with a 3 band Graphic Eq used them.
The LT in a sealed box gave a small box for the driver to sound as good in a larger box. Also lends itself to the need for less timber as bracing isn't really required, so its lighter,( important for mobile use car or PA). Plus, yep its possible to use the driver below its Fs and the possible downside is a massive amp to drive it.
I was looking at the reasons why every manufacturer and his dog, used ports on there boxes. Small box, maybe not nessarcerily a big amp, because the ported box was louder, but chiefly thinking, maybe theres a way around that steep roll off too.
Richie00boy (Hello Sir), LT in the car is ideal, just the benefits of LT and port to give a smaller box, means more room in the car than the equivellent sealed and a lighter load. Maybe this would be a key factor with Mobile DJ's too. I've done some "Roadying", for a DJ, done my back in many a time on those 15's he had. Four in the back of a long wheel-base Transit, decks, light rigs, records, cds and players, amps and stands with a couple of boxes of cable to boot!
But not trying to get out of this forum, splitting between Car and PA, but home use would come into it.
And lastly, can I just add, my Mordaunt Short MS40's have their ports stuffed with my wife's dish cloths. Could she have these back?, and could the ports come back into use, if I changed my Sealed LT for a Reflex? Or more likely, what would happen there?
Cheers, somthing interesting to read is always enjoyable. Thankyou
Mike
I can understand all the pitfalls of doing this. At the end of the day, I always read that a ported box is smaller than its equivillent sealed, a ported is louder, thats why evey cheapo megawatt, Matsui, plastic, all in one with a 3 band Graphic Eq used them.
The LT in a sealed box gave a small box for the driver to sound as good in a larger box. Also lends itself to the need for less timber as bracing isn't really required, so its lighter,( important for mobile use car or PA). Plus, yep its possible to use the driver below its Fs and the possible downside is a massive amp to drive it.
I was looking at the reasons why every manufacturer and his dog, used ports on there boxes. Small box, maybe not nessarcerily a big amp, because the ported box was louder, but chiefly thinking, maybe theres a way around that steep roll off too.
Richie00boy (Hello Sir), LT in the car is ideal, just the benefits of LT and port to give a smaller box, means more room in the car than the equivellent sealed and a lighter load. Maybe this would be a key factor with Mobile DJ's too. I've done some "Roadying", for a DJ, done my back in many a time on those 15's he had. Four in the back of a long wheel-base Transit, decks, light rigs, records, cds and players, amps and stands with a couple of boxes of cable to boot!
But not trying to get out of this forum, splitting between Car and PA, but home use would come into it.
And lastly, can I just add, my Mordaunt Short MS40's have their ports stuffed with my wife's dish cloths. Could she have these back?, and could the ports come back into use, if I changed my Sealed LT for a Reflex? Or more likely, what would happen there?
Cheers, somthing interesting to read is always enjoyable. Thankyou
Mike
Svante said:
...that is why I lowered Fb (fh) in my example above.
By increaseing box size? The already poor transient response of a vented system is worsened by moving to a non-optimal size enclosure for the driver.
forr said:Hi all,
For those interested by Macauley's articles, send me an email.
Yes please, email sent.
Re: Interesting tosay the least.
A ported box is usually larger than it's sealed counterpart. However, as you note the ported box will go louder and with less drive, and have a lower -3dB point. That is why they are popular in consumer electronics - bang for buck.
mikee55 said:I always read that a ported box is smaller than its equivillent sealed, a ported is louder, thats why evey cheapo megawatt, Matsui, plastic, all in one with a 3 band Graphic Eq used them.
A ported box is usually larger than it's sealed counterpart. However, as you note the ported box will go louder and with less drive, and have a lower -3dB point. That is why they are popular in consumer electronics - bang for buck.
Oops
I thought they were smaller. I stand corrected.
Thankyou Sir, (pupil still learning)
Mike
A ported box is usually larger than it's sealed counterpart
I thought they were smaller. I stand corrected.
Thankyou Sir, (pupil still learning)
Mike
MJL21193 said:
By increaseing box size? The already poor transient response of a vented system is worsened by moving to a non-optimal size enclosure for the driver.
Actually I kept the box size the same and lengthened the vent.
Could you elaborate on what you mean by non-optimal size?
Svante said:
Could you elaborate on what you mean by non-optimal size?
Hi Svante,
Wow, port must be long.
Isn't it true that driver specs dictate the size box, length port, diameter port?
There is an optimal size enclosure for any driver in a vented system to give best results.
I read through the Bob Cordell article (which I found before but didn't read). He pans the other methods of bass equalization as brute force approach or requiring too much amp power to drive, while promoting an equalized vented solution.
I don't think there are too many who believe vented speakers sound better than sealed.
Disadvantages of a vented box: poor transient response, port noise, double impedance peaks, increased size and over-excursion below Fb.
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