[Technic]

Originally Posted by hkkuf

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.

I don't think that once you select Flat you can adjust any of the filters... the suggestion is to use High pass at 50Hz and then adjust the bass boost to protect the subs and to see if you like how it sounds like that.

[ElectroVoice]

Originally Posted by Technic

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.



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.



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

Config. I
Use the same amp (Alphasonic), same speakers (2 x 4 Ohm): connecting each speaker straight to each amp's output will yield its normal power of 50w RMS X 2.

Config. II
Use the same amp (Alphasonic), same speakers (2 x 4 Ohm): Wire the speakers in series, the load= 8 Ohms. Connect them to the amp's bridged terminals, this will yield about 120w RMS X 1 + increase damping factor.

Go to any reputable, experienced audio shop, and they tell you the same thing.

Have you ever seen an 8-speaker system (including 2 12" subwoofers) powered by a 45w amp? that's right, 22.5w RMS x 2, a Rockford Fosgate Punch 45. That's what a high grade amp with ultra damping factor is capable of. The Civic wowed the judges every time we competed. It sounded like a 300W system.

Sorry. I think I got you confused AGAIN.

[ElectroVoice]

Originally Posted by hkkuf

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 have mentioned that my Alpine headunit comes with a 'BassEngine' switch. With all that setting in place, when I switch on the BassEngine switch, it adds about 2~3db of bass. Even at this level, the subs are pumping out tight, deep bass, and no sign of breaking up.

Did you know BMW started incorporating 'separates' (multiple speakers for different frequency spectrum) since the early 90s?! (One of our car audio buddies had a 1991 BMW 750iL) I think they are the frontiers in this category. Unlike amplifiers, the cost difference between producing good speakers and lousy speakers is very slight; it's all about branding in speakers. (years ago, when people are paying $300 for a set of MB Quart separates, we were able to find identical set for $110). Did you know JL started manufacturing their speakers in China back in the early 90s? Does anybody care, as long as they sound great??

I cannot emphsize enough that BMW does give us decent speakers to play with, and this Blaupunkt amp is consistent with its brand. Lastly, not all 'watts' are not created equal; did you know that most car audio manufacturers state their specs based on 14.4V, not 12V?

If you have followed everything I stated, since the beginning of this thread, stop worrying, enjoy the music.

[Technic]

Originally Posted by ElectroVoice

Config. I
Use the same amp (Alphasonic), same speakers (2 x 4 Ohm): connecting each speaker straight to each amp's output will yield its normal power of 50w RMS X 2.

Config. II
Use the same amp (Alphasonic), same speakers (2 x 4 Ohm): Wire the speakers in series, the load= 8 Ohms. Connect them to the amp's bridged terminals, this will yield about 120w RMS X 1 + increase damping factor.

I sent an email to the Alphasonik tech department asking for the actual power rating at 8 ohms in a bridged configuration of this PMZ1502A amp to settle this argument for once and for all.

Go to any reputable, experienced audio shop, and they tell you the same thing.

No, thanks... I like to get my facts from myself.

Have you ever seen an 8-speaker system (including 2 12" subwoofers) powered by a 45w amp? that's right, 22.5w RMS x 2, a Rockford Fosgate Punch 45. That's what a high grade amp with ultra damping factor is capable of. The Civic wowed the judges every time we competed. It sounded like a 300W system.

Sorry. I think I got you confused AGAIN.

If I let you confuse me, I'll be confused.

The Rockford Fosgate Punch 45 in reality is not a 22.5W RMS x 2 at 4 ohms amp, ElectroVoice. It is a 753W max amplifier, with 79W RMS x 2 at 4 ohms/251W RMS x 1 at 2 ohms.


http://www.crutchfieldadvisor.com/S-...45.html?page=3

No wonder that that system that you are quoting above "sounded like a 300W system"... the sucker was in fact a 753W system. Of course there is enough power to drive 8 speakers, as long as you wire them to extract those 753W max/251W RMS x 1 at 2 ohms.

Let's stick with facts, please... again, a lot of people are watching this thread and getting ideas to upgrade their system. There is at least two documented posts of blowing OEM subs in this thread. There must be some responsability in what we post and that would involve sticking with the facts.

[ElectroVoice]

Originally Posted by Technic

I sent an email to the Alphasonik tech department asking for the actual power rating at 8 ohms in a bridged configuration of this PMZ1502A amp to settle this argument for once and for all.

No wonder that that system that you are quoting above "sounded like a 300W system"... the sucker was in fact a 753W system. Of course there is enough power to drive 8 speakers, as long as you wire them to extract those 753W max/251W RMS x 1 at 2 ohms.

Let's stick with facts, please... again, a lot of people are watching this thread and getting ideas to upgrade their system. There is at least two documented posts of blowing OEM subs in this thread. There must be some responsability in what we post and that would involve sticking with the facts.

I started this thread to share my experiences with this board, because I felt I owe it to this board for some knowledge on the E90 when I need to install the Alpine Nav. headunit. I am glad many of you followed the thread, and did this quick and inexpensive upgrade. I think I've done my job, and it's time to move on. I am not here to argue with anyone, but through my long time experience with car audio, I've learned, what happens on the field beats whatever manufacturers trying to tell you; car audio, like anything else, takes experience and skill. This will be my last post on this board. Good luck.

p.s. Never pay retail or buy the newest line of products.