sealed or ported.... - Audio & Electronics Forum

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sealed or ported....
Monday, August 07, 2006 10:34 AM
ok guys i have 2 of these 10" subs: rfp4410 HE



polypropylene woofer cone
large roll foam surround
CONsealer gasket hides mounting screws and provides an airtight seal
frequency response 32-200 Hz
power range 200 watts RMS
peak power handling 400 watts
sensitivity 85.5 dB
4-ohm impedance
top-mount depth 5-3/8"
sealed box volume 0.625-1.5 cubic feet
ported box volume 0.75-1.75 cubic feet

and this amp: Kenwood KAC929 1000watt



Sound Effects Bass Boost
Response Bandwidth 5 - 50000 Hz
Signal-To-Noise Ratio 100 dB
Max Output Power / Channel Qty 300 Watts x 2
Continuous Power / Channel Qty 150 Watts x 2
High Level Inputs Yes
Input Signal Voltage 0.2 - 5V
Crossover Channel Qty 2 channel(s)
Crossover Slope 18 dB/octave
Low Pass Frequencies 50 - 200 Hz
Bass Boost Frequency 90 Hz
Bass Boost Gain 0 to +12dB, 0 to +6dB
Distortion Factor 0.08%
Amplifier Output details 150 Watt - 4 Ohm - 20 - 20000 Hz - THD 0.08% - 14.4V DC - 2 channel(s)
230 Watt - 2 Ohm - THD 0.8% - 14.4V DC - 2 channel(s)
Soft Start / Quiet Turn-On Yes
Features Input level controls, gold-plated connectors, mono/stereo switch, filter switch

for awhile now i have been running these is a somewhat small sealed box which i dont think was even completely sealed because i can hear air coming out where the connectors are on the side when i push the sub in... but anyways i really think i could get more out of these subs then i am so i want to get a proper box for these..... if i got ported should i be looking for this " ported box volume 0.75-1.75 cubic feet " ???? i remember when i tried running wires parallel the amp overheats and cuts off... please point me in the right direction will this mess =)

comment away please !




Re: sealed or ported....
Tuesday, August 08, 2006 8:56 AM
Well right off the bat you've stated that the box is suspect so that's where I'd start. Considering the low power at hand I'd say ported all the way. If built and tuned properly you wont lose sq and it will be more efficient. The "0.75cf to 1.75cf" is ballpark range of the size you could build before driver and port displacement. I think 1.5 to 1.75 (per sub) would be a little more realistic tuned around 35hz.

As far as the amp I believe you're trying to run it bridged to two subs in parallel, which that amp is not going to do. A plainjane class A/B two channel amp bridged is already running at two ohms, so trying to wire the subs in parallel you're dropping to one ohm. With the ported box wiring each channel to a single sub with the stereo/mono signal switch set to mono is about the best you're gonna do without upgrading the subs/amp. If that's the case then there are others here that are more knowledgeable as far as bang for buck in you given price range.



Re: sealed or ported....
Tuesday, August 08, 2006 9:30 AM
All I am going to say is this: Elemental Designs
Check into them.


GIT 'ER DONE!
Re: sealed or ported....
Tuesday, August 08, 2006 9:39 AM
Yeah I will be ordering my next enclosure from them. I will probably have to cut my trunk out a little bit because right now with the amp in there, the box has nowhere to go except left or right a couple inches.



Re: sealed or ported....
Wednesday, August 09, 2006 5:25 AM
well i found where the air was coming out of the sealed box so i sealed it all up and i cant hear any air leak like before so im gonna give this another go seeing if it makes a difference.

my amp says it 2 ohm mono stable......
so how do i go about hooking this up to get the best i can without overheating?
when bridged and ran parralel amp overheated and cut off so...
before i just bridged these 2 4ohm subs in series,.....does that give me 2 ohms?
and is that my best choice?




Re: sealed or ported....
Wednesday, August 09, 2006 9:45 AM
Bridging a two channel amp to a 4 ohm sub effectively puts your amp at 2 ohms, so you won't be able to run two subs in parallel because the amp will see a 1 ohm load. Running the subs in series with the amp bridged will put the amp at a 4 ohm load. If you're dead set on keeping the subs the a class D mono amp is your best bet as they will operate at a 2 ohm load with two 4 ohm subs in parallel.



Re: sealed or ported....
Wednesday, August 09, 2006 11:58 AM
ah i see, i dont want to get any new stuff till this stuff dies, so basically bridging these in series is my best bet i guess. thanks



Re: sealed or ported....
Wednesday, August 09, 2006 8:52 PM
If that's the case I would go ported since that'll only set you back the cost of some mdf, wood glue, and caulk if you're looking for a little more bump.




Re: sealed or ported....
Wednesday, August 09, 2006 9:45 PM
ohvrolla wrote:Bridging a two channel amp to a 4 ohm sub effectively puts your amp at 2 ohms, so you won't be able to run two subs in parallel because the amp will see a 1 ohm load. Running the subs in series with the amp bridged will put the amp at a 4 ohm load. If you're dead set on keeping the subs the a class D mono amp is your best bet as they will operate at a 2 ohm load with two 4 ohm subs in parallel.


Bridging a 2 channel amp to a 4ohm sub gives a 2 ohm load? .. uhh... k...


wysiwyg wrote:i would say they bang, they don't really pound so much. but if
you want to bump, then they will bump and hit real hard and a lot good.

LOL
Re: sealed or ported....
Wednesday, August 09, 2006 10:23 PM
Straight from Kenwood about bridging this amplifier KAC929 manual. Right at the bottom it has a big caution about bridging the amp to speaker with an impedance of less than 4 ohms. Also look at the ratings of 230 x 2 at 2ohms and 460 x 1 bridged. As stated before when the amp is bridged to a 4 ohm sub it is effectively a 2 ohm load on the amp and this is why the amp puts out the same power into 2 channels at 2 ohms as it does bridged to a 4 ohm sub.

This is straight from basic car audio electronics website for those who need to learn the basics of bridging a 2 channel amplifer and what effect is has as far as the load on the amp is concerned click here for lesson




Re: sealed or ported....
Thursday, August 10, 2006 5:00 AM
^

good stuff thanks.

my amp is best bridged, so i have to hook them up in series. the one thing i still didnt get was do i set it to mono or stereo?




Re: sealed or ported....
Thursday, August 10, 2006 9:54 AM
Quote:

All I am going to say is this: Elemental Designs.



What does this have to do with anything. All of a sudden people are hyping them and for what. They are inexpensive subs whose reviews have been anything but great.
Re: sealed or ported....
Thursday, August 10, 2006 10:13 AM
blkfire00 wrote:
Quote:

All I am going to say is this: Elemental Designs.



What does this have to do with anything. All of a sudden people are hyping them and for what. They are inexpensive subs whose reviews have been anything but great.


I hate how people start trying to spend someone else's money. I think it's pretty clear that Brian is trying to get the most out of what he has instead of throwing what he has in the basement and starting fresh. ED's may very well be better than the fosgates, but the the fosgates should be enough to add some bass to the system and not everyone wants to wake up the neighbors the next street over.

Brian I'd keep the amp set to stereo and bridge the amp to the subs in series. If you run mono you're only amplifying the left channel so I don't think the amp can be bridged since the right channel isn't being used. In the manual it even shows using two amps when setting them to mono. One per speaker.




Re: sealed or ported....
Thursday, August 10, 2006 10:16 AM
thank you for a direct answer =)



Re: sealed or ported....
Thursday, August 10, 2006 4:17 PM
ohvrolla wrote:Straight from Kenwood about bridging this amplifier KAC929 manual. Right at the bottom it has a big caution about bridging the amp to speaker with an impedance of less than 4 ohms. Also look at the ratings of 230 x 2 at 2ohms and 460 x 1 bridged. As stated before when the amp is bridged to a 4 ohm sub it is effectively a 2 ohm load on the amp and this is why the amp puts out the same power into 2 channels at 2 ohms as it does bridged to a 4 ohm sub.

This is straight from basic car audio electronics website for those who need to learn the basics of bridging a 2 channel amplifer and what effect is has as far as the load on the amp is concerned click here for lesson


NOTE:
Some people say that when an amplifier is bridged onto a 4 ohm load, it 'sees' a 2 ohm load. While it is true that the same current flows whether the amp is bridged on a 4 ohm load or a 2 ohm stereo load, the amplifier is driving a 4 ohm load across its outputs. A single 4 ohm speaker can never be a 2 ohm load.

lol...straight off the site....


wysiwyg wrote:i would say they bang, they don't really pound so much. but if
you want to bump, then they will bump and hit real hard and a lot good.

LOL
Re: sealed or ported....
Thursday, August 10, 2006 9:28 PM
ohvrolla wrote:Bridging a two channel amp to a 4 ohm sub effectively puts your amp at 2 ohms, so you won't be able to run two subs in parallel because the amp will see a 1 ohm load. Running the subs in series with the amp bridged will put the amp at a 4 ohm load. If you're dead set on keeping the subs the a class D mono amp is your best bet as they will operate at a 2 ohm load with two 4 ohm subs in parallel.


^^^^ I thought that was what I was saying. It's all good though as long as the op can decipher what we're saying



Re: sealed or ported....
Friday, August 11, 2006 12:58 AM
It just puts out the same amount of wattage at 4 ohm mono as in 2 ohm stereo...the amp does not see a 2 ohm load


wysiwyg wrote:i would say they bang, they don't really pound so much. but if
you want to bump, then they will bump and hit real hard and a lot good.

LOL
Re: sealed or ported....
Friday, August 11, 2006 9:31 AM
Chris H wrote:It just puts out the same amount of wattage at 4 ohm mono as in 2 ohm stereo...the amp does not see a 2 ohm load



bingo


and if your running your amp bridged it is a mono signal not stero


http://www.flickr.com/photos/sndsgood/ https://www.facebook.com/#!/Square1Photography
Re: sealed or ported....
Friday, August 11, 2006 10:01 AM
Seems like we're splitting hairs here, bottom line is the amp draws the same current at 4 ohm mono as 2 ohm stereo which is why I said it effectively puts the amp at 2 ohms because all the op knows is his amp is "2 ohm stable."

I'll make it easier to understand and help clear up the confusion. When the amp is bridged it will use the positive portion of the sine wave from one channel and the negative portion of the sine wave from the other channel to increase (hopefully double) the voltage applied to the speaker which will draw more current (directly proportianal to voltage increase) from the amplifier. Therefore the amp pulls the same current at 4 ohm mono as 2 ohm stereo.

I know, I know, I should have just said this earlier.




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