[Technic]

Originally Posted by ElectroVoice

I've heard of Alphasonic, but never seen one at work. It sounds like the amp is under-powered, or it might not be in perfect working condition.

You can get more power from the amp by bridging the amp (it states that it is bridgable) Connect the subs in series, then follow the manufacturer's direction on bridging the amp (it might be marked on the amp). Since the result impedence is 8 ohms, you will only get a slight, but noticeable boost. You might consider buying another identical amp, and have both of bridged, one for each amp.

p.s. You might get some extra thump from tuning the bass control on the headunit.

It is the other way, ElectroVoice... the subs would have to be wired in parallel (2 ohms total impedance) for an amp to increase the power output (if 2 ohms stable, of course). Series wiring will decrease the amp output, as less current will be flowing as there is more impedance at the same voltage. Unless the amp is one of those with automatic output compensation (same output regardless of impedance) this is the way it usually works.

In the case of this particular amp, there is something that also need to be considered: although it says that it is bridgeable, it only lists 150W x 1 for 4 ohms and nothing for 2 ohms. So it is not clear that it will be stable at 2 ohms in a mono ouput configuration... so beware.

[jcarlucci1]

Originally Posted by ElectroVoice

I've heard of Alphasonic, but never seen one at work. It sounds like the amp is under-powered, or it might not be in perfect working condition.

You can get more power from the amp by bridging the amp (it states that it is bridgable) Connect the subs in series, then follow the manufacturer's direction on bridging the amp (it might be marked on the amp). Since the result impedence is 8 ohms, you will only get a slight, but noticeable boost. You might consider buying another identical amp, and have both of bridged, one for each amp.

p.s. You might get some extra thump from tuning the bass control on the headunit.

I had to turn the bass controls on the head unit way down..there was just too much volume coming from the subs..not sure why you think its underpowered..anyway, already blew one of the subs..think I was just pushing them too hard. If anyone wants to sell me a stock sub, pm me..gonna try again.

[jcarlucci1]

Originally Posted by Technic

It is the other way, ElectroVoice... the subs would have to be wired in parallel (2 ohms total impedance) for an amp to increase the power output (if 2 ohms stable, of course). Series wiring will decrease the amp output, as less current will be flowing as there is more impedance at the same voltage. Unless the amp is one of those with automatic output compensation (same output regardless of impedance) this is the way it usually works.

In the case of this particular amp, there is something that also need to be considered: although it says that it is bridgeable, it only lists 150W x 1 for 4 ohms and nothing for 2 ohms. So it is not clear that it will be stable at 2 ohms in a mono ouput configuration... so beware.

+1..8 ohms will give me less power..and the amp is not 2 ohm stable in mono..I will probably just get the 2 ohm sws-8's and give them 75 watts each with this amp.

[ElectroVoice]

Originally Posted by jcarlucci1

I had to turn the bass controls on the head unit way down..there was just too much volume coming from the subs..not sure why you think its underpowered..anyway, already blew one of the subs..think I was just pushing them too hard. If anyone wants to sell me a stock sub, pm me..gonna try again.

I'd have that amp checked.

Even though the Blaupunkt is, what I consider, a mid-grade amp, it allowed me to turn my volume more than 3/4 way up; it was an ear-deafening level without much distortion.

Years ago, I bought my first Fosgate Punch amp, it was a $400 amp which I got used for $120. It turned out to be defective. I've learned my lesson then.

If I remember correctly, Alphasonic has pretty good specs. The most common situation in which people have blown their speakers, is under-powering the speakers, due to distortion. Don't risk a $200 speaker on that amp!!!

[ElectroVoice]

Originally Posted by Technic

It is the other way, ElectroVoice... the subs would have to be wired in parallel (2 ohms total impedance) for an amp to increase the power output (if 2 ohms stable, of course). Series wiring will decrease the amp output, as less current will be flowing as there is more impedance at the same voltage. Unless the amp is one of those with automatic output compensation (same output regardless of impedance) this is the way it usually works.

In the case of this particular amp, there is something that also need to be considered: although it says that it is bridgeable, it only lists 150W x 1 for 4 ohms and nothing for 2 ohms. So it is not clear that it will be stable at 2 ohms in a mono ouput configuration... so beware.

When an amp is stable at 2 ohms, meaning it may only be bridged to 4 Ohms, no less. You are suggesting to feed the amp's bridged output into a 2 ohm load, in essence, the amp is 'seeing' only 1 Ohm!! Only a handful of amps will be able to do that (Orion HCCAs, certain competition Phoenix Golds ).

Since he's got 2 4-Ohm speakers, in order to get more power out of it without changing the speakers, is to run an 8-Ohm configuration, that way, the amp sees a 4-Ohm load. Why bother, you ask? Bridging, under same load, usually increase output by about 15% (in his case, 2 4-Ohm output vs. 1 8-Ohm), more importantly, bridging increase damping factor, which helps in harder hitting bass; that's why Orion, Precision Power and Rockford Fosgate are more commonly used in competitions, for powering subwoofers, because their amps have the industrys' highest damping factor rating.

My '88 Mustang GT competed in 50+ sound competitions, in the 250~499Watt class, during the late 80s and early 90s; I have placed in the top 3 in 1/2 of those shows. I have helped more than 100 people put together their systems back then.

[jcarlucci1]

Originally Posted by ElectroVoice

When an amp is stable at 2 ohms, meaning it may only be bridged to 4 Ohms, no less. You are suggesting to feed the amp's bridged output into a 2 ohm load, in essence, the amp is 'seeing' only 1 Ohm!! Only a handful of amps will be able to do that (Orion HCCAs, certain competition Phoenix Golds ).

Since he's got 2 4-Ohm speakers, in order to get more power out of it without changing the speakers, is to run an 8-Ohm configuration, that way, the amp sees a 4-Ohm load. Why bother, you ask? Bridging, under same load, usually increase output by about 15% (in his case, 2 4-Ohm output vs. 1 8-Ohm), more importantly, bridging increase damping factor, which helps in harder hitting bass; that's why Orion, Precision Power and Rockford Fosgate are more commonly used in competitions, for powering subwoofers, because their amps have the industrys' highest damping factor rating.

My '88 Mustang GT competed in 50+ sound competitions, in the 250~499Watt class, during the late 80s and early 90s; I have placed in the top 3 in 1/2 of those shows. I have helped more than 100 people put together their systems back then.

I don't understand this..bridged into 4 ohms the amp puts out 150 watts rms..now if you run it into 8 ohms its gonna see about 100 watts again..it was already putting out 100 watts...50x2..right? Doesnt matter anyway, looks like I need to get a new amp and new speakers now..time to start over. I really wanted to keep this amp though since its the only one that fits in that "secret compartment"

[spazmcdougal]

Originally Posted by arabbmw

i know this is gonna annoy some people, but does this void warrant? i know if it does i can just pull it out before service, but will it throw a code or anything?

My answer from the dealership was "Yes". I blew the sub under my passenger seat and when I took my car in they said that the blown speaker was caused by a non OEM head unit etc.... and would not replace the speaker on warranty. Currently I'm looking for something to replace the unde the seat sub, preferably something the exact dimensions.

[jcarlucci1]

Originally Posted by spazmcdougal

My answer from the dealership was "Yes". I blew the sub under my passenger seat and when I took my car in they said that the blown speaker was caused by a non OEM head unit etc.... and would not replace the speaker on warranty. Currently I'm looking for something to replace the unde the seat sub, preferably something the exact dimensions.

Earthquake sws-8

[Technic]

Originally Posted by ElectroVoice

When an amp is stable at 2 ohms, meaning it may only be bridged to 4 Ohms, no less. You are suggesting to feed the amp's bridged output into a 2 ohm load, in essence, the amp is 'seeing' only 1 Ohm!! Only a handful of amps will be able to do that (Orion HCCAs, certain competition Phoenix Golds ).

I did not even suggested what you are saying. What I was saying is that your initial suggestion of the series wiring with this Alphasonic is incorrect, as 8 ohms will not increase this amp output... or any amp output under the same conditions.

Since he's got 2 4-Ohm speakers, in order to get more power out of it without changing the speakers, is to run an 8-Ohm configuration, that way, the amp sees a 4-Ohm load. Why bother, you ask? Bridging, under same load, usually increase output by about 15% (in his case, 2 4-Ohm output vs. 1 8-Ohm), more importantly, bridging increase damping factor, which helps in harder hitting bass; that's why Orion, Precision Power and Rockford Fosgate are more commonly used in competitions, for powering subwoofers, because their amps have the industrys' highest damping factor rating.

There is a confusion here, as two different conditions are made to look as one single condition when they are not.

An amp with a total load of 8 ohms in a single channel will "see" 8 ohms regardless of how that load is wired (parallel or series). So the total power output will be the same as long as the total load is the same at the same channel. The total load in a single channel will inversively affect the total output power; the higher the load the less power, the lower the load, the higher the power.

Now, to bridge requires a stereo amp -two channels at least. Therefore bridging under the same load will increase power if the amp is capable of bridging and supply more power while bridged. This makes sense just because now you are in effect increasing the capability of the amp to supply more current into the same load because you are summing two channels into one. The one channel current supply constraint is gone. More current, more power at the same load.

We are seeing it in the specs of this Alphasonic: 50W x 2 at 4 ohms, 150W x 1 at 4 ohms. However, the same rule apply because we are back to a single channel condition: the total load will inversively affect the total output power. An increase to 8 ohm total load from 4 ohms in this case will decrease the total output of 150W to perhaps 75W to 80W depending on this amp internals.

My '88 Mustang GT competed in 50+ sound competitions, in the 250~499Watt class, during the late 80s and early 90s; I have placed in the top 3 in 1/2 of those shows. I have helped more than 100 people put together their systems back then.

Good for you, ElectroVoice... but you are still confused.

[Technic]

Originally Posted by jcarlucci1

I had to turn the bass controls on the head unit way down..there was just too much volume coming from the subs..not sure why you think its underpowered..anyway, already blew one of the subs..think I was just pushing them too hard. If anyone wants to sell me a stock sub, pm me..gonna try again.

The Logic7 sub amp power output to the OEM subs is 70W max into 4 ohms per channel. This Alphasonic was putting out ~100W max into 4 ohms (50W RMS per channel)... there would be some real "pushing hard" to blow one of them or you should take a look to the wiring/amp gains in case there is something wrong. Normally that slight increase in power is not enough to blow an OEM speaker if the amp is wired/tuned right.

You do not want to blow the replacement also.

[hkkuf]

Originally Posted by Technic

The Logic7 sub amp power output to the OEM subs is 70W max into 4 ohms per channel. This Alphasonic was putting out ~100W max into 4 ohms (50W RMS per channel)... there would be some real "pushing hard" to blow one of them or you should take a look to the wiring/amp gains in case there is something wrong. Normally that slight increase in power is not enough to blow an OEM speaker if the amp is wired/tuned right.

You do not want to blow the replacement also.

Just a quick question. At 70W max per channel, what would be the approximate RMS wattage per channel?
The Blaupunkt is 75W RMS per channel, I believe... I don't want to blow my subs, so is there a max gain level (on the amp) that I should be careful of?

EDIT:
According to this table at http://www.e90post.com/forums/showpo...82&postcount=2, the sub for Logic 7 (Top HiFi) has 70 W per channel, does that usually mean 70 W max?

[Technic]

Originally Posted by hkkuf

Just a quick question. At 70W max per channel, what would be the approximate RMS wattage per channel?
The Blaupunkt is 75W RMS per channel, I believe... I don't want to blow my subs, so is there a max gain level (on the amp) that I should be careful of?

EDIT:
According to this table at http://www.e90post.com/forums/showpo...82&postcount=2, the sub for Logic 7 (Top HiFi) has 70 W per channel, does that usually mean 70 W max?

That rating usually means max, unless RMS (root mean square) is stated somewhere; roughly 50% of the max is RMS, depending of the amp design.

There is a gain and bass boost adjustment in the Blaupunkt amp; I do understand that the Blaupunkt amp is cheap but it is difficult to me to make sense of putting that much power to the OEM subs -that are rated to handle only half of that continous power (not peak) to begin with in the case of the Logic7 subs; in the base HiFi system the OEM subs are just rated at 40W max and at 2 ohms, so it will be some 6 times the continous power rating - and then choke the amp to keep them from blowing.

The whole idea should be to improve the whole sub performance, air movement and power to move that air to the optimum level. Not just power alone, as the air movement is limited by the mechanics of the OEM subs. Yes, they will sound slightly better with an increase in power as there is more force moving that air, but too much power will exceed the set mechanics of the subs.

That's the reason that a much noticiable and stable improvement is the combination of more power with stronger and more efficient cone mechanics within the same enclosure... new amp and subs.

[hkkuf]

Thanks Technic.
I'm glad that I got to do this blaupunkt installation because 1) I wanted a better performance out of my subs at a reasonable price/effort, 2) it got me to do the necessary research I would have never done otherwise.
Since I'm not an audiophile, I think I'm okay with the gained power from Blaupunkt for now. While I'm not sure if it's as good as 10 inchers in the trunk (I'm a bit embarrassed to say I've never been in a car with that set up), this was a fun weekend project, and I really like the remote bass control since I don't have to go into the idrive to adjust the bass level.

The only thing that worries me is blowing the subs by getting overly eager with the remote, as I suspect that warranty (related to Subwoofers) has gone down the drain. I'd like earthquake sws on my car, but at the moment it sounds like more work than I'm willing to put in. (getting under the front seats and putting in spacers to fit the speakers to the enclosure, etc.)

Until I blow my stock subs or get extrememly bored with their performance, I don't think I'm going to upgrade them.

Maybe ElectroVoice can answer this better. You said in your first post "Set the low pass frequency to about 90 Hz, setting the bass boost on about half way, and the remote bass level to about 3 quarters". That sounds like the amp will be pumping in more power than your stock subs were made to handle according to the table I linked above. Do you feel like the subs are handling them ok?

PS. If 40W max at 2 ohms, is that like 20W max at 4 ohms and 10W RMS at 4 ohms?
If so, then wouldn't it be 7.5 times, rather than 6 times the continuous power rating?

[Technic]

Originally Posted by hkkuf

Thanks Technic.
I'm glad that I got to do this blaupunkt installation because 1) I wanted a better performance out of my subs at a reasonable price/effort, 2) it got me to do the necessary research I would have never done otherwise.
Since I'm not an audiophile, I think I'm okay with the gained power from Blaupunkt for now. While I'm not sure if it's as good as 10 inchers in the trunk (I'm a bit embarrassed to say I've never been in a car with that set up), this was a fun weekend project, and I really like the remote bass control since I don't have to go into the idrive to adjust the bass level.

The only thing that worries me is blowing the subs by getting overly eager with the remote, as I suspect that warranty (related to Subwoofers) has gone down the drain. I'd like earthquake sws on my car, but at the moment it sounds like more work than I'm willing to put in. (getting under the front seats and putting in spacers to fit the speakers to the enclosure, etc.)

Until I blow my stock subs or get extrememly bored with their performance, I don't think I'm going to upgrade them.

Maybe ElectroVoice can answer this better. You said in your first post "Set the low pass frequency to about 90 Hz, setting the bass boost on about half way, and the remote bass level to about 3 quarters". That sounds like the amp will be pumping in more power than your stock subs were made to handle according to the table I linked above. Do you feel like the subs are handling them ok?

PS. If 40W max at 2 ohms, is that like 20W max at 4 ohms and 10W RMS at 4 ohms?
If so, then wouldn't it be 7.5 times, rather than 6 times the continuous power rating?

I think that this type of discussion is required in this thread because the E9x has two types of sound systems in the USA, with two different impedance ratings for the subs (a 2 ohm and a 4 ohm) at two different maximum power ratings (40W and 70W respectively).

With all this said, Logic7 systems OEM subs are more capable of handling this Blaupunkt amp power output in paper than the HiFi OEM subs, just because of their impedance (4 ohms) and power max handling (70W max); they are just more robust than the HiFi OEM subs for this amp power outputs. Remember, this amp is putting out a continous 120W (240W max) to each 2 ohm OEM subs rated at just 40W max by the OEM amp. Even if in fact the 2 ohms OEM subs are capable of handling, let's say 100W max, the Blaupunkt RMS power output per OEM sub is still more than their max rating...

I would be more concerned about how to limit the lower end of the Blaupunkt low pass filter (subsonic) frequencies than the upper end, as the real problem could be trying to reproduce deep sub bass (40 Hz and below) with all that much power out of a sub that in reality is more like a sub/mid bass driver. Most of the distortion would be there...

We are seeing already a couple of posts of blown OEM subs so the more information is out there the better is for everybody to make their decision.

[hkkuf]

Originally Posted by Technic

I would be more concerned about how to limit the lower end of the Blaupunkt low pass filter (subsonic) frequencies than the upper end, as the real problem could be trying to reproduce deep sub bass (40 Hz and below) with all that much power out of a sub that in reality is more like a sub/mid bass driver. Most of the distortion would be there...

How would I limit the lower end of the low pass filter? I only saw one knob that says low pass frequency. Should I play around with the HU equalizer? I'm a bit confused here. This is all the controler that's on Blaupunkt.


I think mine is set at Crossover: low, Low pass: around 100hz, bass boost: 6db, gain: I use the remote.

thanks

[jcarlucci1]

Originally Posted by Technic

The whole idea should be to improve the whole sub performance, air movement and power to move that air to the optimum level. Not just power alone, as the air movement is limited by the mechanics of the OEM subs. Yes, they will sound slightly better with an increase in power as there is more force moving that air, but too much power will exceed the set mechanics of the subs.

Thank you for saying this.. it is what I have been trying to say but not doing a good job at it. Even with 50 watts rms, the subs are at their "mechanical limit" the cones are overextending, and you can hear it when you turn the volume up. That is why mine blew. Even though specs say the factory amp is 70 watts, I would bet its probably 20 watts rms..

[jcarlucci1]

Originally Posted by hkkuf

How would I limit the lower end of the low pass filter? I only saw one knob that says low pass frequency. Should I play around with the HU equalizer? I'm a bit confused here. This is all the controler that's on Blaupunkt.

You cant..that why I bought the amp that I did..it has a "subsonic filter" which filters out the super low frequencies. Didnt make a difference, still blew the subs.

[hkkuf]

Originally Posted by jcarlucci1

Thank you for saying this.. it is what I have been trying to say but not doing a good job at it. Even with 50 watts rms, the subs are at their "mechanical limit" the cones are overextending, and you can hear it when you turn the volume up. That is why mine blew. Even though specs say the factory amp is 70 watts, I would bet its probably 20 watts rms..

Is keeping gain at low level going to relieve the pressure to the subs?

[Technic]

Originally Posted by hkkuf

How would I limit the lower end of the low pass filter? I only saw one knob that says low pass frequency. Should I play around with the HU equalizer? I'm a bit confused here. This is all the controler that's on Blaupunkt.


I think mine is set at Crossover: low, Low pass: around 100hz, bass boost: 6db, gain: I use the remote.

thanks

I don't think that this amp has a subsonic filter (if so, please jcarlucci1 let us know what is the value), so you should reduce some of the lowest frequency in the OEM HU EQ and just look for any distortion creeping up depending of your volume and adjust the gains/bass boost/OEM HU EQ bass frequencies as required to keep that distortion -if any- in check.

You can try using the high pass at 50Hz and increase the bass boost (if this combination is possible, some amps permit bass boost with low pass setting only) to see if the subs can handle that without any distortion at high volume.

Sometimes a pop can be mistaken for "punch"... too many pops and the sub is gone.

[hkkuf]

Originally Posted by Technic

I don't think that this amp has a subsonic filter (if so, please jcarlucci1 let us know what is the value), so you should reduce some of the lowest frequency in the OEM HU EQ and just look for any distortion creeping up depending of your volume and adjust the gains/bass boost/OEM HU EQ bass frequencies as required to keep that distortion -if any- in check.

You can try using the high pass at 50Hz and increase the bass boost (if this combination is possible, some amps permit bass boost with low pass setting only) to see if the subs can handle that without any distortion at high volume.

Sometimes a pop can be mistaken for "punch"... too many pops and the sub is gone.

I don't think there is subsonic stuff on the amp either.
I thought high pass was only used when the crossover was set to "high" or "flat", I think I read that in the owner's instruction, but I can be wrong.

What exactly does bass boost do? Does it basically give more volume to the bass?

[Technic]

Originally Posted by hkkuf

I don't think there is subsonic stuff on the amp either.
I thought high pass was only used when the crossover was set to "high" or "flat", I think I read that in the owner's instruction, but I can be wrong.

What exactly does bass boost do? Does it basically give more volume to the bass?

In this case you will be using the high pass at 50Hz as your "poor man's non-subsonic filter" as anything below 50Hz will be attenuated. Then use the bass boost to increase the bass around that 50Hz to compensate for the lack of below-50Hz frequencies.

Again, I don't know how low these OEM subs can go without popping, but I do know that OEM subs are cheap by nature and design. And if the SWS-8 can go in paper down to 30 Hz (with a max power handling of 150W RMS/300 peak) then I don't think that the OEM subs can go lower than 40Hz. So 50Hz could be an acceptable lower limit for safety and enjoyment.

Bass boost is a parametric EQ set at a particular frequency at a particular octave (the range of frequencies below and above that set frequency). In this case it is at 45Hz fixed -no octave is listed-, so it could mean that only the 45Hz frequency is adjusted in level and nothing else. And that could mean also that bass boost is only operational if low pass is selected as the crossover...

Just check it out...

[hkkuf]

Originally Posted by Technic

In this case you will be using the high pass at 50Hz as your "poor man's non-subsonic filter" as anything below 50Hz will be attenuated. Then use the bass boost to increase the bass around that 50Hz to compensate for the lack of below-50Hz frequencies.

Again, I don't know how low these OEM subs can go without popping, but I do know that OEM subs are cheap by nature and design. And if the SWS-8 can go in paper down to 30 Hz (with a max power handling of 150W RMS/300 peak) then I don't think that the OEM subs can go lower than 40Hz. So 50Hz could be an acceptable lower limit for safety and enjoyment.

Bass boost is a parametric EQ set at a particular frequency at a particular octave (the range of frequencies below and above that set frequency). In this case it is at 45Hz fixed -no octave is listed-, so it could mean that only the 45Hz frequency is adjusted in level and nothing else. And that could mean also that bass boost is only operational if low pass is selected as the crossover...

Just check it out...

So I guess you are suggesting I set the crossover at "flat", set high pass at 50 and low pass around 100, is that right?

I think you are right about the bass boost being only operational if low pass is selected.

Oh well, I'll play around with it, and if it blows the stock subs, Earthquake sws it is.