milosz

In the sedan the main amp is up along the top of the trunk area, on the left, essentially under the rear package shelf area. It is covered by the trunk lining.

In the sedan, the amp for the rear 10-inch subwoofer is clipped directly to the back of the driver.

milosz

So my guestimates were within 2 dB of the actual power levels.

Interesting that Bose gave you that info, everything I've read about Bose is that they are quite secretive.

llebcire

Anything new to report?

Curious if you ever implemented a crossover on the mids and what happened?

I have a set of Morel Maximo 6 components and I believe the crossover is 3.5 KHz - too low? I'd also like to see if I could incorporate the 1" soft domes in the sails. This spring I'll probably install my Zapco 5 channel but only use the 5th channel for my Alpine Type R in a sealed enclosure (original series with HAMR) and feed it from my AudioControl LCQ-1 high level for bass control. Maybe use the other 4 channels to beef up the doors but I'm not sure it would be necessary.

-Eric

VibrantSedan13

iTrader: (3)

Can someone clarify a few things for me?

So from my understanding, the 3.5 inch driver along with the 1" inch tweeters are 4ohms. But it looks like if I replace them, the stock bose amp wont really allow the speakers to perform better. Does that sound right?

Also there seems to be a lot of confusion about the center dash speaker, whether it's supposed to play music or not.

If I replace all of my speakers with the standard 4ohm stuff, and replace the stock bose amp with something else, this would have to sound better right?

I just added a Rockford Fosgate P300-12, and OMG it sounds so nice. Now the issue I'm having is being able to hear alot of voices/trebel out of the front. The sub is completely over powering it. I'm trying to see whether I can just replace the speakers or do I need to replace the amp as well. And after doing all of this, will it actually sound better.

VibrantSedan13

iTrader: (3)

So I called up Bose Automotive Customer Service today, and here is the info that they gave to me.

Both the main amp and the Sub amp only puts out 2ohms.

However as you will see below, some speakers are actually 4ohms. Does this mean that if you replace them with 2 ohm they will be louder?

Suppsedly the main amp is 225 watts. Which by the specs they gave me, is wrong. Anyways, here they are:

75 Watts each for the front doors.
15 Watts each for the rear doors.
15 Watts for the center speaker.

As you see, that comes out to 195

The Sub Amp supposedly puts out 75 Watts.

So a grand total of 300 Watts is what they are telling me.

Here are the speaker specs.

1 inch Tweeters in the sail panel, which is wired parallel with the 3.5 inch driver in the door panel. This tweeter is a 4ohm speaker.

3.5 Inch speakers in the front door panel, which is also a 4ohm speaker.

10 Inch Woofer in the front door panel is a 2ohm speaker.

They could not tell me how the 75 watts were shared among the tweeters, 3.5 driver and 10 inch woofers.

The rear speakers are 6.5 Inch and are a 2ohm speaker.

The center speaker is a 3.5 inch and also a 4ohm.

The rear deck sub is a 10 inch 2ohm sub.

The main amp is supposed to be a true 4 channel with a tiny 5th channel built in.

Channel 1- 75 Watts going to front left door.
Channel 2- 75 Watts going to front right door.
Channel 3- 15 Watts going to left rear door.
Channel 4- 15 Watts going to right rear door.
Mini Channel 5- 15 Watts going to front center speaker.

llebcire

yellowjacket83

I'm curious about this as well...I have added a subwoofer but would like to do this as well if it will help with the quality of the sound. I'll have the door panels off soon to add some sound deadener and chase down some annoying rattles...may play with adding a crossover as well while i'm in there.

milosz

Just last week, I added a MiniDSP 2X4 Balanced into the system to apply EQ to the front channels only, keeping the stock Bose drivers and trunk-mounted stock Bose amp / EQ / crossover unit (see diagram) I'd been planning this for a long time but only just got around to it. I got matching female and male connectors of the same type used in the harness that comes from the head unit and plugs into the Bose amp, and used these as a basis to insert the MiniDSP into the signal path. I unplugged the factory harness from the trunk-mount Bose amp and plugged it into the matching socket of my DIY harness to feed signal into the MiniDSP, then plugged the DIY harness coming out of the MiniDSP into the Bose amp's socket. Didn't have to cut any factory wires in the G37.

NOTE: My car is a sedan.

With the subwoofer I added previously, and the sophisticated EQ afforded by the MiniDSP, I have made the system sound much better without all the expense and effort of fitting totally new drivers and amps. The difference is night and day. I've tamed the really nasty, peaky treble response that Bose designed in and also increased the 400~800 Hz level to fill in the major midrange "hole" in the response. I've also applied minor smoothing EQ at other frequencies as well. Using measurements and also some tweaking by ear I've got the system sounding much better now. The MiniDSP costs $115.00 and it's also important to use the MiniDC to provide isolated power for the MiniDSP and to properly delay amp turn-on until after the MiniDSP is on. https://www.minidsp.com/products/min...p-balanced-2x4

Oddly, the sonar beeps now only work about half the time when backing up. The sonar green-yellow-red graphics show up on the rearview screen, but the audible beeps come and go. A bit baffling but not something I'm terribly worried about, the vast improvement in sound is worth losing the sonar beeps.

yellowjacket83

That's awesome! Thanks for passing all of the information and research on to the community...I've been studying this thread for hours and its great stuff. Using the miniDSP to tweak the sound with minimal changes to the factory system is most likely the path I will take. Looking at the miniDSP on their website it talks about plug-ins (one free with purchase)...which one did you use for this tuning?

milosz

I used the 2-Way Advanced 2.1 plugin https://www.minidsp.com/images/docum...%20plug-in.pdf

Although the MiniDSP 2x4 can be used as a crossover, I did not use the crossover filters. I only used two outputs - there are four outputs, typical active crossover use would be output #1 = low-pass to left woofer, Output #2 high-pass to left tweeter, output #3 low-pass to right woofer, output #4 high-pass to right tweeter.

But, since I am only using EQ, and not crossover functionality, I simply do it this way: Output #1 = LEFT Output # 2 NOT CONNECTED Output #3=RIGHT Output #4=NOT CONNECTED

I think there is some way to use the "DSP Power" that would normally be employed to run the crossover filters as a complex EQ filter using biquads, but as there are 6 parametric EQ bands prior to the crossover stage and 6 more after the crossover stage, well 12 parametirc EQs were enough for my needs, I just set the crossover filters to BYPASS and left it at that.

FYI i used manual settings, and did not calculate any biquads. A biquad is a set of coefficients that sets up the EQ filter in a complex way; you make a measurement of a driver or a system using something like OmniMic or Room Equlaization Wizard (REW) measurment software with a PC and a calibrated microphone; OmniMic or REW can output the measured frequency response in a file that is understood by MiniDSP 2-Way Advanced 2.1 plugin; the plugin takes this frequency response file and does the math on it to calculate the set of biquad coefficients which the FIR DSP hardware uses to create a filter curve that is the reverse of the measurement- so if you use OmniMic and measure a huge peak at 50 Hz and maybe a slump from 1,000 to 2,500 then another peak at 5,000 Hz, taking that measurement file and feeding it to the plug-in, the plug-in will calculate a filter that should bring response back to flat.

This works OK when using the MiniDSP for speakers in a room, where you can get fairly meaningful measurements. But inside a car there are so many reflections and problems figuring out where to place the measuring mic that getting a frequency response measurement that is really representative of how the system sounds to a human listener is hard if not impossible, so this process of making a measurement of the playback sound then using the plug-in to calculate the proper filters really doesn't work all that well. Instead, I use the plug-in's on-screen EQ controls to make my adjustments. I do make some measurements but they can only act as a general guide to tuning the EQ. The ear can do some things when hearing music that measurements using a swept tone cannot- for example, on midrange and treble events in music the ear / brain can discriminate between the musical sound and reflections inside the car to a fair degree; the mic cannot. So a person might hear less midrange in the music than the measurement mic hears from it's swept tone - the mic hears both the tone and it's reflections which may have more amplitude than the sound event as perceived by the ear, because the listener can discriminate between the sonic event and it's reflections (to a degree) - you can compensate this when measuring by using gating, but that really is only useful for the lower frequencies and become impractical higher up.

ANYWAY it's best to make some measurements to guide you but the way the music sounds to you has got to be your final criteria. And I find I have to make adjustments over several sessions, over several days - my hearing gets saturated after a while and I can't tell if a change I just made is right or wrong. Also, if I'm tired, stressed out from something going on in my life, in a hurry, or just feeling negative, I'm going to react differently to my EQ choices. So, by doing the EQ, then driving for a few days and listening to various kinds of music and radio, then making some more adjustments, then listening for a few days- eventually I end up with something that works.

Please note that I also have a subwoofer amp driving a sealed box 12" sub in the trunk, the signal for this is the signal from the main Bose amp in the trunk- it has a subwoofer output, must be a crossover in the thing and maybe some EQ too - I disconnected the connector going to the amplifier that drives the factory Bose 10" sub in the parcel shelf, and just picked the line level subwoofer channel signal out of that connector and used that to drive my Alpine amp. The Alpine amp has a bass EQ, a level pot and a low pass filter on it that I can twiddle also, and I used this to get the low bass sounding the way I wanted. I also put in a switch on the sub box that lets me reverse the phase of the sub - this switch, in one position the bass sounded "boomy" and in the other it was tighter and deeper. So, if you have an added sub, be sure to experiment with reversing it's phase. I have a switch, but you can just switch the + and - wires from the amp to the speaker's binding posts, that's another way to switch the phase of the sub. (My switch actually switches the + and - sides of the balanced line signal that goes to the balanced-to-unbalanced converter, but switching the leads to the sub driver does the same thing.)

Here's some notes on using the MiniDSP for complex filters: https://www.minidsp.com/support/comm...he-minidsp-2x4

The article doesn't address my setup exactly, but it gives you some ideas about how this technology can be used.

I've attached the plug-in settings that I used- you can load this file into the plugin and you'll have the EQ settings that I am currently using.... which will probably change as I go along. Right-click the link and SAVE AS to grab the file=> MILOSZ-EQ

The hardest part of all this was getting the socket and plug for the head unit - to -Bose amp harness and wiring up my DIY stuff in between to insert the MiniDSP into the signal chain. I bought a Bose G37 amp from a boneyard that they just cut the harness on - so I took the socket out of the amp and they had left about a foot of the plug- side of the harness plugged in so I had both sides- the socket and the plug. I then carefully followed the wiring diagram - some signals, like the rear speaker signals, and the "mode" signal* I wired straight through, but the "AMP ON" and left and right channels I diverted into the MiniDSP.

* The "MODE" signal comes from the head unit, and it tells the amp to go into "Driver Stage" mode or "Regular" mode. There has got to be some DSP inside the Bose amp doing this kind of thing, as the "Driver Stage" seems to change channel-to-channel timing, levels and and frequency response also. It's kind of a neat thing. I never use it, I just leave it set at "Normal" - but it's cool nonetheless.

yellowjacket83

Thanks again...that helps a lot! I have a simple 10" Rockford Fosgate off-the-shelf sealed sub/amp combo currently that has a phase switch and bass boost/level adjust ***** that I can play with but I have it wired to the high-level output of the Bose subwoofer amp. This makes for some erratic behavior from the sub...too much bass in some situations, too little in others it seems. I ordered the TX-1A that you used to go from balanced inputs to the regular RCA inputs on the sub amp so i'll be wiring it like you have it once that comes in. Based on this comment in the previous post i'm a little confused though - "...signal for this is the signal from the main Bose amp in the trunk- it has a subwoofer output, must be a crossover in the thing and maybe some EQ too" does that mean the signal coming from the main Bose amp is crossed over? I thought, reading further up in this thread, that the signal for the subwoofer coming from the main amp was not crossed over/EQ'd and that the signal modifications were done in the small subwoofer amp...if you could please clarify that would be great.

As for the driver stage setting...I go back and forth, lol. I had an E46 BMW as my previous ride that had the HK system with the driver stage button that I would switch back and forth with as well.

milosz

NOTE - now that temperatures are dropping here in Chicago - it's 38° F tonight - I seem to be experiencing a longer turn-on delay from the MiniDC which adds a little delay to the amp turn-on signal so that the MiniDSP comes on and is stable before the amps are turned on. See https://www.minidsp.com/products/acc...inidc-isolator

Delaying the amps a little keeps any "thump" out of the speakers that would come from the MiniDSP's series output capacitors charging up. Used to be maybe 2 seconds, today it was like 30 seconds. Seems like it could be the effect of the cold on the parts that set the time constant, though it seems like here in the 21st century we should have moved beyond using an RC circuit to set a delay time, heck they used 555's for this kind of thing as far back as the 1970's.... or maybe with the cold some of my wiring has come loose at a connection point, the MiniDSP uses these little screw-down terminals, maybe one is loose. I'll have to check. It's not that annoying but I need to look into it.

reybeast

Milosz, pm sent.

yellowjacket83

Interesting...I installed same setup as you a couple of weeks ago and so far, so good. Overall, I love the setup. I haven't played with it much other than setting the EQ to the same settings you have but just having the ability to play around with it is awesome.
I'll post later on if I encounter any issues as the temperatures drop in Georgia over the next few months. Also, I'm definitely not a fan of the screw terminals...I mounted the Mini DC and the DSP unit where I can easily access them to check the screws periodically.

milosz

>>I mounted the Mini DC and the DSP unit where I can easily access them to check the screws periodically.<<

Mine is on the back of the subwoofer box in the trunk, not too bad for access. I'm going to have to go back there with my DVM and see what is going on, see if the "AMP TURN ON" signal is losing it's way somewhere among the connections, or if the MiniDC delay has gotten longer somehow.