Hi,
Just another quick question my second amp is a 4 channel cadence Q4000 and am currently running one 10" 200watt 4ohm sub bridged on the second channel. I'd like to add more, should I stick to another 4ohm 10" or could I add a 12" or 15", or maybe even two more 2 ohm 10"s wired in parallel? (The amp is 2x200 watt at 4 ohm bridged) I'm just wondering what would sound best.
Thanks for any ideas of suggestions,
Gav
Replies (13)
Victor on 08/5/2005 23:56:38
more specs on your amp needed here to give u better advice..
compvr15s on 08/6/2005 00:04:24
if that is rms power i dont see why cou couldnt add a 10 or a 12. having two different size subs is isnt a bad idea, can set the xover on the 10 to cut off at maybe 80-100hz and then have the 12 cut off at 80 or something like that, know what i mean, let the 10 play some of the higher freqs.... but adding a matching 10 would work too, wont gain much spl here. but cant tell you what to do or not to do.... but definitly nothing wrong with adding another sub....
Victor on 08/6/2005 00:23:30
Well what he has not cleared here is that is he gonna use just one bridged ch, or both the front and the rear in bridged mode..
( he says he has the sub to the second channel in bridged mode.. is he using the other 2 channels to power other speakers , or is it spare to add another sub ...?????)
also since the amp gives out 200wrms per bridged channel @ 4 ohms, he also has to see that he wires the subs for a 4 ohm load , cause as we know the amp wont work healthy at a 2ohm load in bridged mode..
lets see another aspect too.. if he uses 2 subs of 200wrms each on the same bridged channel @ 4 ohms then both the subs will be getting 100wrms each,
adding another sub will add a 3db spl, but again , since he is reducing the power going to each sub by half ( as we know doubling / halving the power will give a 3 db difference ) there is again a loss of 3 db's there.. so what he is planning to gain is being lost , and he is also spending much more money for no noticable difference expect for the fact of having more subs in his car..
about X overs, i guess the rear channel on tha amp will have an LPF of 80Hz, while the front are full range .. so again he will have to spend on LP Xovers..
I personally dont see this as a viable project.. instead if he uses a good 12" sub rated at 200wrms in an EBS enclosure , or 4th order BP he will gain a lot more on SPL side then what he is planning right now..
comments...???
Victor...
compvr15s on 08/6/2005 02:05:38
yea i guess i never thought about that, i just assumed you were using channel one bridged for one some and then channel 2 bridged for your sub now... you want to put 2 subs on the channel you are using now for your one sub you are not going to gain anything, but if you plan on using all four channels to power the subs, ch 1&2 for sub A and ch 3&4 for sub B this will be ok, but if you are using the first channels to power interior speakers then i would not bother on geting another sub....
supagav on 08/6/2005 06:38:09
Sorry I should have given you more info.... my appologies!
The first amp I'm using is a 2 channel which is powering the front set of components, thats cool. The second amp is what I want to use to run the subs...
I have one spare stereo channel, as I'm only running one bridged sub @ 4 ohms. I was just wondering whether you thought it was better to have A: two matched subs, or B: two different subs set to handle different frequencies, or maybe C: two extra 2 ohms subs wired in parallel to a 4 ohms load?
I was planning to use channel A& B for the new sub/s and C&D for the 10" I'm running at the moment.
Here's some more info on the amp:
4x60 @ 4 ohms stereo
4x100 @ 2 ohms stereo
2x200 @ 4 ohms mono bridged
Freq Response: 20Hz-30Khz
Thanks,
Gav
supagav on 08/6/2005 08:30:09
Sorry, I meant C: two 2 ohm subs wired in series to a mono 4 ohm load
Victor on 08/6/2005 10:43:10
Good news for you...
Just had a look at the amp specs on the cadence site..
http://www.cadencestore.com/cadence_manuals/Q%20Amp%20Manual.pdf
Its a very userfriendly amp i guess.. Its got 50Hz to 250 Hz adjustable Xovers at 12db/octave on the front as well as the rear with a adjustable upto +12db bass boost.
Now regarding the subs...
You have both the options open, a similar size sub as well as a different size sub ( lets put out the option of adding more than 1 sub here, lets keep it to just a sub onto each bridged channel )
If you get another 10" ,200wrms @ 4ohm sub you will get louder and tighter sound, and you will have the advantage of uniformity in your car.
You can also use a different size sub say a 12" or a 15", and Xover it at 80HZ ( or upto 100 if desired ).hence the 12" will play 50Hz to 80Hz/100Hz while the 10" can play 80Hz/100Hz to 250 Hz So the freq will be distributed among both the subs and under ideal situations this shud perform better, cause the subs will have to perform in a limited bandwidth.
But here you may have to face issues like a major drop or bump at the Xover frequencies.
In either ways I would not use more than 2 subs on that amp.
If personally i had to do it, I would take another 10" sub and install both of them in an EBS enclosure for best performance.
Hope that helps..
comments..??
Victor...
swez on 08/6/2005 13:08:45
Victor has pointed out a good line for this application. The amp has the power and flexibility to get the job done and you can choose whatever size sub you desire too. Just make sure it's a 4 ohm coil when bridging the A/B channels.
As for best bang for your buck, the enclosure will have the greatest effect on the bass you can achieve here. Having a well matched box to your sub(s) are one of the most overlooked aspects of a good/great sounding bass machine. High efficiency subs can help too, but the box is generally the primary factor.
Hey Victor, can you go a bit deeper on the term "EBS"? Im' not clear on that one at the moment.
Swez
Victor on 08/6/2005 16:43:28
EBS- Extended Bass Shelf.
This is vented enclosures with unusual volume.The idea is to intentionally design the enclosure to be 125-175% larger than the optimum calculated volume and then tune the enclosure much lower than optimum as well.
as a result you will get extended low frequency response. If you plot the curve on a graph you will see a "shelf" in the curve just above the tuning frequency before rools off sharply.
This type of enclosure wil exhibit extended low frequency response, and increased efficiency at the lower frequencies but decreased efficiency at higher frequencies.
Cut-off rate can be as high 36 dB/octave below fB.
Transient response is not so good when compared to sealed enclosure.The enclosure size is huge. The power handling is reduced by 25-50%.
The sub may reach Xmax sooner above fB.
The overall impact of the bass is much softer.
with such an alignment the lower frequency band that is below 50Hz performs tremendously well.
In general, low frequency is extended and efficiency increased at the expense of reduced efficiency at higher frequencies.
Hope that helps..
Victor...
supagav on 08/6/2005 17:34:00
Thats great, definately some ideas to think about. The 2nd 10" sounds the best option, so I'll investigate some new enclosures.
Thanks for all your time and help,
Gav
swez on 08/6/2005 18:06:48
Thanks Victor! An "Executive Summary" (brief & to the point, pros/cons) would suffice for the moment. I should have asked for that in the beginning.
Care to summerize EBS? (let me try first)
1. Much larger enclosure used (150% of typical, +/-25%)
2. Port/vent tuning below optimal PTF ( Fs, +0/-5 Hz.)
Pros: Extended low bass performance; good efficiencies at PTF range; performs notably better below 50 Hz.
Cons: Sharp attenuation upper bass region; very large enclosure; below optimal transient response; power handling of sub reduced 25-50%
Does that about cover it?
Swez
Victor on 08/7/2005 00:28:41
Yes Swez, That should cover it all,
Just this much to add..
The tuning frequency of the enclosure should be equal to or close to the subs resonance frequency ( Fs ).
Victor...
PS. Have a look at this for an example and a frequency response plot, It should tell you a lot about the behaviour of an EBS.
http://www.diysubwoofers.org/prt/ported8.htm
swez on 08/7/2005 11:51:57
OK, I made a change in PTF parameters:
Port/vent tuning below optimal PTF ( Fs, +5/-0 Hz.)
Does that pretty much square with your understanding of EBS design guides?
Swez
Just another quick question my second amp is a 4 channel cadence Q4000 and am currently running one 10" 200watt 4ohm sub bridged on the second channel. I'd like to add more, should I stick to another 4ohm 10" or could I add a 12" or 15", or maybe even two more 2 ohm 10"s wired in parallel? (The amp is 2x200 watt at 4 ohm bridged) I'm just wondering what would sound best.
Thanks for any ideas of suggestions,
Gav
Replies (13)
Victor on 08/5/2005 23:56:38
more specs on your amp needed here to give u better advice..
compvr15s on 08/6/2005 00:04:24
if that is rms power i dont see why cou couldnt add a 10 or a 12. having two different size subs is isnt a bad idea, can set the xover on the 10 to cut off at maybe 80-100hz and then have the 12 cut off at 80 or something like that, know what i mean, let the 10 play some of the higher freqs.... but adding a matching 10 would work too, wont gain much spl here. but cant tell you what to do or not to do.... but definitly nothing wrong with adding another sub....
Victor on 08/6/2005 00:23:30
Well what he has not cleared here is that is he gonna use just one bridged ch, or both the front and the rear in bridged mode..
( he says he has the sub to the second channel in bridged mode.. is he using the other 2 channels to power other speakers , or is it spare to add another sub ...?????)
also since the amp gives out 200wrms per bridged channel @ 4 ohms, he also has to see that he wires the subs for a 4 ohm load , cause as we know the amp wont work healthy at a 2ohm load in bridged mode..
lets see another aspect too.. if he uses 2 subs of 200wrms each on the same bridged channel @ 4 ohms then both the subs will be getting 100wrms each,
adding another sub will add a 3db spl, but again , since he is reducing the power going to each sub by half ( as we know doubling / halving the power will give a 3 db difference ) there is again a loss of 3 db's there.. so what he is planning to gain is being lost , and he is also spending much more money for no noticable difference expect for the fact of having more subs in his car..
about X overs, i guess the rear channel on tha amp will have an LPF of 80Hz, while the front are full range .. so again he will have to spend on LP Xovers..
I personally dont see this as a viable project.. instead if he uses a good 12" sub rated at 200wrms in an EBS enclosure , or 4th order BP he will gain a lot more on SPL side then what he is planning right now..
comments...???
Victor...
compvr15s on 08/6/2005 02:05:38
yea i guess i never thought about that, i just assumed you were using channel one bridged for one some and then channel 2 bridged for your sub now... you want to put 2 subs on the channel you are using now for your one sub you are not going to gain anything, but if you plan on using all four channels to power the subs, ch 1&2 for sub A and ch 3&4 for sub B this will be ok, but if you are using the first channels to power interior speakers then i would not bother on geting another sub....
supagav on 08/6/2005 06:38:09
Sorry I should have given you more info.... my appologies!
The first amp I'm using is a 2 channel which is powering the front set of components, thats cool. The second amp is what I want to use to run the subs...
I have one spare stereo channel, as I'm only running one bridged sub @ 4 ohms. I was just wondering whether you thought it was better to have A: two matched subs, or B: two different subs set to handle different frequencies, or maybe C: two extra 2 ohms subs wired in parallel to a 4 ohms load?
I was planning to use channel A& B for the new sub/s and C&D for the 10" I'm running at the moment.
Here's some more info on the amp:
4x60 @ 4 ohms stereo
4x100 @ 2 ohms stereo
2x200 @ 4 ohms mono bridged
Freq Response: 20Hz-30Khz
Thanks,
Gav
supagav on 08/6/2005 08:30:09
Sorry, I meant C: two 2 ohm subs wired in series to a mono 4 ohm load
Victor on 08/6/2005 10:43:10
Good news for you...
Just had a look at the amp specs on the cadence site..
http://www.cadencestore.com/cadence_manuals/Q%20Amp%20Manual.pdf
Its a very userfriendly amp i guess.. Its got 50Hz to 250 Hz adjustable Xovers at 12db/octave on the front as well as the rear with a adjustable upto +12db bass boost.
Now regarding the subs...
You have both the options open, a similar size sub as well as a different size sub ( lets put out the option of adding more than 1 sub here, lets keep it to just a sub onto each bridged channel )
If you get another 10" ,200wrms @ 4ohm sub you will get louder and tighter sound, and you will have the advantage of uniformity in your car.
You can also use a different size sub say a 12" or a 15", and Xover it at 80HZ ( or upto 100 if desired ).hence the 12" will play 50Hz to 80Hz/100Hz while the 10" can play 80Hz/100Hz to 250 Hz So the freq will be distributed among both the subs and under ideal situations this shud perform better, cause the subs will have to perform in a limited bandwidth.
But here you may have to face issues like a major drop or bump at the Xover frequencies.
In either ways I would not use more than 2 subs on that amp.
If personally i had to do it, I would take another 10" sub and install both of them in an EBS enclosure for best performance.
Hope that helps..
comments..??
Victor...
swez on 08/6/2005 13:08:45
Victor has pointed out a good line for this application. The amp has the power and flexibility to get the job done and you can choose whatever size sub you desire too. Just make sure it's a 4 ohm coil when bridging the A/B channels.
As for best bang for your buck, the enclosure will have the greatest effect on the bass you can achieve here. Having a well matched box to your sub(s) are one of the most overlooked aspects of a good/great sounding bass machine. High efficiency subs can help too, but the box is generally the primary factor.
Hey Victor, can you go a bit deeper on the term "EBS"? Im' not clear on that one at the moment.
Swez
Victor on 08/6/2005 16:43:28
EBS- Extended Bass Shelf.
This is vented enclosures with unusual volume.The idea is to intentionally design the enclosure to be 125-175% larger than the optimum calculated volume and then tune the enclosure much lower than optimum as well.
as a result you will get extended low frequency response. If you plot the curve on a graph you will see a "shelf" in the curve just above the tuning frequency before rools off sharply.
This type of enclosure wil exhibit extended low frequency response, and increased efficiency at the lower frequencies but decreased efficiency at higher frequencies.
Cut-off rate can be as high 36 dB/octave below fB.
Transient response is not so good when compared to sealed enclosure.The enclosure size is huge. The power handling is reduced by 25-50%.
The sub may reach Xmax sooner above fB.
The overall impact of the bass is much softer.
with such an alignment the lower frequency band that is below 50Hz performs tremendously well.
In general, low frequency is extended and efficiency increased at the expense of reduced efficiency at higher frequencies.
Hope that helps..
Victor...
supagav on 08/6/2005 17:34:00
Thats great, definately some ideas to think about. The 2nd 10" sounds the best option, so I'll investigate some new enclosures.
Thanks for all your time and help,
Gav
swez on 08/6/2005 18:06:48
Thanks Victor! An "Executive Summary" (brief & to the point, pros/cons) would suffice for the moment. I should have asked for that in the beginning.
Care to summerize EBS? (let me try first)
1. Much larger enclosure used (150% of typical, +/-25%)
2. Port/vent tuning below optimal PTF ( Fs, +0/-5 Hz.)
Pros: Extended low bass performance; good efficiencies at PTF range; performs notably better below 50 Hz.
Cons: Sharp attenuation upper bass region; very large enclosure; below optimal transient response; power handling of sub reduced 25-50%
Does that about cover it?
Swez
Victor on 08/7/2005 00:28:41
Yes Swez, That should cover it all,
Just this much to add..
The tuning frequency of the enclosure should be equal to or close to the subs resonance frequency ( Fs ).
Victor...
PS. Have a look at this for an example and a frequency response plot, It should tell you a lot about the behaviour of an EBS.
http://www.diysubwoofers.org/prt/ported8.htm
swez on 08/7/2005 11:51:57
OK, I made a change in PTF parameters:
Port/vent tuning below optimal PTF ( Fs, +5/-0 Hz.)
Does that pretty much square with your understanding of EBS design guides?
Swez
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