I have had a squeal-type noise coming from the speakers in my Maxima, for some time.
I'm in the middle of replacing the window regulator on the front driver-side door, and have the door panel completely opened up. I replaced the Bose speaker in that door with a Rockford speaker, but this did not eliminate the squeal.
I believe that the window regulator on the passenger-side door will need to be replaced soon, and plan on replacing the Bose speaker in that door with the other Rockford speaker, when that door panel is taken apart.
Could someone please explain what is causing the squeal-type noise to occur, and whether my plan to replace the Bose speakers with Rockford speakers in both doors is likely to eliminate the squeal. Are there other parts of the audio system which I will need to replace?
Thanks very much, in advance, for helping me diagnose and repair this problem.
You can't just swap out the Bose speakers. The Bose system is specifically designed to work together - they are low-impedance speakers with built in amps.
Search the groups, there was a recent thread in which Codifus and dgeesaman covered the alternatives and using aftermarket equipment within the constraints of an existing Bose setup.
Thanks for pointing me to the recent Codifus thread, concerning a Bose Head Unit and aftermarket speakers.
Sorry, but I need someone to explain the basics to me. I do not know what a head unit is.
Also, when I replaced the Bose speaker with the Rockford, I connected the Rockford to the existing amp, inside the housing.
Is it possible that the existing Bose amp is causing the squeal? Do I need to remove the Bose amp from the housing, before I put the door panel back together, if I use the Rockford speaker?
If someone could please describe a typical head-unit/amp/speaker setup, including the name of the manufacturer(s), it would be most helpful.
First let me answer your issue. I beleive your left speaker amp is faulty. To verify that it is indeed the problem, swap the left and right front amps. In the 95-99 Maxima, the front amps are twins, and the rear amps are twins. You can swap left and right and everything will still work fine. If the squeal goes to the right speaker now, then we know it is definitely the amp that needs replacing. Get a replacement Bose amp and only use the Bose speaker. Places like carstereohelp.com sell them. Avoid this Bose replacement amp called the BRA001 you may find on other sites. It's crap. I fell into that trap once.
Now, onto understanding Bose.
A head unit is the heart of your stereo, the radio part, so to speak. It usually contains the radio, amplifier, and on more sophisticated systems, the cassette, cd player etc. It in the dash. On more elaborate system which have external amps and subs, the head unit provides RCA outputs like your home stereo which feed a standard line level signal out to the external amplifiers.
Mixing and matching with Bose systems, if done right, is quite a challenge. This is because the audio industry follows the standard and Bose has their own. From the head unit example I gave above, you would surmise that the head unit has the amplifier, which your Rockford does. But Bose does things quite differently. To get a better uderstanding, I will simply explain how Bose works. I'm not a Bose enineer, just a regular guy who studied the system somewhat well.
The bose head unit puts out a "Bosefied" signal. It's stronger than a line level signal but not strong enough to drive a speaker to loud volume levels. It is amplified, but not enough. Weird. I also beleive that this Bose signal has automatic loudness. It's a very nice, sophisticated feature. Once the signal reaches the amp, it is then amplified AND equalized it for the speaker it's connected to. The front amps contour the sound differently than the rear amps do. You have to keep the amp mated to its speaker, but you can still swap left and right.
A quick dscription of standard audio, like your Rockford unit. The Rockford head unit contains the radio, amp etc. It can connect to standard speakers, not Bose amps or speakers. It can also connect to standard external amplifier because it puts out a standard line level signal. The speaker outputs, usually 4, put out the same exact signal to all the speakers, well, in stereo, the lefts are identical and the rights are identical. Put it in mono, and all 4 speakers are receiving the exact same signal. You get the picture.
Because of those differences, if you want to replace the Bose system in parts, but want to keep the Bose sound, the very high quality way to go would be by using the equipment from
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The PD4 can integrate your Rockford head unit into the existing Bose setup very well. At $150, it may be a bit more than you'd like to spend, but I have
1st hand experience using it. Not only does it keep the Bose sound, it makes it better. Better because the replaced Head unit has better quality components than the standard head unit in the Bose head unit. The CD DAC is of better quality etc. The system is not any louder since you're still using the same Bose amps, but it is indeed better, in sound and quality of features.
Other less expensive options include the very commone Bose adapters. These adapters attach to the output (the Bosefied signal I mentioned earlier), convert it to a line level signal, then feed it to standard amps speakers etc. The drawback to them is that they take an amplified signal, convert it to a line level signal, only to be amplified again. Distortion is greater. Most peole don't notice or car for this diffrerence, The distortion isn't so great that you cant listen, it just not the best qulity solution. If you just want to get the basic system working, then you may want to go this route.
I want to express my thanks to Nirav and Steve for their help and comments in diagnosing the problem in my Bose system, and especially to Codifus for taking the time and effort to describe the basics of my Bose system and also non-Bose systems. After reading Codifus' explanation, I finally understood the nature of the problem I was dealing with. It was nice of Codifus to take the time to write such a detailed explanation of the differences between Bose and non-Bose systems, and is very much appreciated.
Since I only had one door panel torn apart ( to repair the window regulator ), I was unable to swap the amps from both doors, to see if the squeal changed doors. Codifus suspected the amp, and Steve suspected the capacitors in the amp.
Unfortunately, I had the window repaired, and was ready to put the door back together before Codifus and Steve posted their replies. I probably was not clear in my description, because I suspect that Codifus may have misunderstood that I only swapped out the Bose speaker in one door for a Rockford speaker in that door, and I did _not_ replace the Bose head unit. The Bose head unit is still in place.
I wish that I could have read Steve's and Codifus' replies before putting the door back together, because I would have done things differently. When I installed the Rockford speaker in the one door, I left the Bose amp in the system, and the Rockford speaker still squealed. Not having a full understanding of Bose vs. non-Bose systems (since I had not then read Codifus' explanation), I went on the Internet, and found out that the small wires carried the signal, and the big wires powered the amp. I cut the small wires and spliced them to the Rockford speaker wires. The squeal went away, but the volume of the system went down ( which I now understand from Codifus' explanation ). I put the door back together at that point, and a couple of days later, Codifus and Steve posted their replies.
So that's where I'm at now. The squeal is gone, so the problem must have been in the amp for the speaker I replaced. I can get by with the lower volume level, except when there's a lot of road noise, then I just can't hear it, and turn off the audio. My game plan is to replace the other Bose speaker with the other Rockford speaker, when the other window fails, and I have to tear the other door apart. At that point, the volume will probably diminish to the point where the system is inaudible, and I will have to replace the Bose head unit with a non-Bose head unit. If anyone can point me to instructions for tearing apart the dash, and replacing the Bose head unit with a non-Bose head unit, I would greatly appreciate it, so I will have the instructions ready when the time comes.
Thanks in advance for any other suggestions or thoughts about how to proceed, after the Bose speakers have been replaced with Rockford speakers.
I hope that I can help someone else in the future, much as you have helped me understand, diagnose and repair my Bose problem.
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