Mids/Highs amp for speakers with different RMS ratings

[Gunk]

I'd appreciate some input on how people generally approach this issue.

I currently have 3.5" Pioneer Pro Series tweeters installed in my dash. (100w RMS)
I was planning on installing the 6.5" mid bass driver from the their same line in my front doors. (110w RMS)
I was thinking that buying a US Acoustics Barbara Ann 4 x 100 Watts RMS @ 4 Ohm amp for these would be a good idea.

I got into my door panel today and could see that I think I have space to install an 8" mid driver in the door instead of the 6.5". Pioneer has an 8" driver in this same line that I could use. It is 180w RMS.
I would need to put a 3/4" thick baffle over the hole to get the depth clearance I need but it looks like my door card will still have room to go back on if I do that.

*** So all that just to ask my main question.
How do you guys choose an amp when speakers have different RMS ratings?
I'm new to this so I there is a lot I don't know. They don't make amps that allow you to turn the gain down on just one channel do they?

I'm trying to push these doors to the max as I'm going to sound treat the inner and outer skin completely with sound deadner and then make a full MLV/CCF barrier for the door card.

Any input is appreciated. Thanks in advance.

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[Gunk]

Additionally,

I bought foam rings to go with the speaker install.
They give you a solid foam circle to install behind the speaker on the outer door skin but as you can see from my picture, the crash bar is right behind the speaker location.

Should I just cut the thing up and go around the crash bar? Maybe try to glue it over top of it?

Of course, if went I with 8" mids here I would be sending these rings back.

 

[honkyg^2]

as far as i know, all 4 channel amps have at least two gain adjustment potentiometers. one for channels 1/2, and one for channels 3/4,.. some have separate gain adjustment for each channel, but usually by more clarity-oriented manufacturers from yesteryear and higher end products of today, although, im sure some budget amps of today have dedicated gains for each channel. i myself have old school hafler and a/d/s/ amplifiers with independent channel gains, for example.

the barbara ann would be fine for your setup when using the 6.5's in a normal signal chain configuration, and you could also opt use ch. 1 and 2 for left, and 3/4 for right to reduce cross-talk if you choose to do so, provided you have an external crossover to adjust the frequency range of each driver pair before amplification with the amplifier's onboard crossovers set to full or off.

if you decide to go with the 8" drivers, you'll probably want (not necessarily need) an amplifier capable of producing the highest rms power rating of the preferred component drivers to be used and configured to a standard signal chain arrangement with your tweeter bank gain dialed down to their rms rating. using amplifiers with much lower ratings than the drivers they supply may leave something left to be desired in response.

as for the speed rings, cutting them around the crash bar will nullify their intended use, so it would be my advice to modify the baffle and door card to get them to fit unmolested.

 

[Gunk]

as far as i know, all 4 channel amps have at least two gain adjustment potentiometers. one for channels 1/2, and one for channels 3/4,.. some have separate gain adjustment for each channel, but usually by more clarity-oriented manufacturers from yesteryear and higher end products of today, although, im sure some budget amps of today have dedicated gains for each channel. i myself have old school hafler and a/d/s/ amplifiers with independent channel gains, for example.

the barbara ann would be fine for your setup when using the 6.5's in a normal signal chain configuration, and you could also opt use ch. 1 and 2 for left, and 3/4 for right to reduce cross-talk if you choose to do so, provided you have an external crossover to adjust the frequency range of each driver pair before amplification with the amplifier's onboard crossovers set to full or off.

if you decide to go with the 8" drivers, you'll probably want (not necessarily need) an amplifier capable of producing the highest rms power rating of the preferred component drivers to be used and configured to a standard signal chain arrangement with your tweeter bank gain dialed down to their rms rating. using amplifiers with much lower ratings than the drivers they supply may leave something left to be desired in response.

as for the speed rings, cutting them around the crash bar will nullify their intended use, so it would be my advice to modify the baffle and door card to get them to fit unmolested.

Thanks for the amazing write up. Much appreciated.

 

[Gunk]

as far as i know, all 4 channel amps have at least two gain adjustment potentiometers. one for channels 1/2, and one for channels 3/4,.. some have separate gain adjustment for each channel, but usually by more clarity-oriented manufacturers from yesteryear and higher end products of today, although, im sure some budget amps of today have dedicated gains for each channel. i myself have old school hafler and a/d/s/ amplifiers with independent channel gains, for example.

the barbara ann would be fine for your setup when using the 6.5's in a normal signal chain configuration, and you could also opt use ch. 1 and 2 for left, and 3/4 for right to reduce cross-talk if you choose to do so, provided you have an external crossover to adjust the frequency range of each driver pair before amplification with the amplifier's onboard crossovers set to full or off.

I wonder if I could bridge that Barbara Ann amp and then drop the gain down on my tweeter channels.

 

[Popwarhomie 5,000+ posts]

What are your plans for crossovers? Active headunit? Or using the amps bandpass crossovers? Those mids only come in 8 ohm IIRC. You don't NEED 180 watts per mid for them to get loud. They have a sensitivity of 96db.

If you are set on running the USA Barbara ann I would look into 4 ohm mids personally.


But yes, it's as simple as tuning the gain down to get less power.

 

[honkyg^2]

I wonder if I could bridge that Barbara Ann amp and then drop the gain down on my tweeter channels.

you could, and have a crapload of overhead power at your disposal, but that's not something i would recommend considering that can be a potential of 3-4 times the power being delivered to your drivers upon large spikes in signal amplitude that can cause catastrophic failure. in addition, you would be reducing a stereo output to a monaural output for w/e bank you bridge, thus, no capability of adjusting the signal response via processing for each separate driver.

 

[Gunk]

What are your plans for crossovers? Active headunit? Or using the amps bandpass crossovers? Those mids only come in 8 ohm IIRC. You don't NEED 180 watts per mid for them to get loud. They have a sensitivity of 96db.

If you are set on running the USA Barbara ann I would look into 4 ohm mids personally.


But yes, it's as simple as tuning the gain down to get less power.

Their 4 ohms.

I was thinking of using the amp's crossover.

TBH, I only chose the Barbara Ann amp because it seemed many people recommend it for SQ. I'm totally open to suggestions. Just not trying to buy the most expensive thing out there.

 

[Gunk]

I guess the real question would be...

Would there be much difference in sound performance from using the 8's instead of the 6.5's if I continue to use the same 100x4 Barbara Ann amp for either one?

 

[Gunk]

Bump. Anybody?

 

[fithwheel]

Generally speaking a larger mid will go lower than a smaller mid but will not go as high as a smaller mid. If the tweeter can't be crossed over low then that'll be an issue.
Probably not a lot of specs on those pioneers? Personally I'd be looking for a tweeter with a low fs to match up to a 8 inch mid. Most of the time you're safe to crossover a tweeter 2x the fs. With at least a 12db slope. Probably would feel a little better using a higher slope depending on the power being used in relation to the tweeters power handling.
You'll start to get beaming if you try to go to high with the larger mid. It's give and take but why you usually see a smaller mid used with larger mids. This is all generally speaking but that's a super tweeter right? Doubt it will go very low. Might be better off with the smaller mid. Most of the time a good 6.5 will go up to 2.5k Hz before it starts to break up (beaming) an 8 1 to 1.5k Hz.
I cross my 8s at 800 where a 2"mid takes over to 5k where the tweeters take over for example. I can go high with my 8 but it's close to the point where the 2 inch mid starts sounding better than the 8