[chuyler1]

the rating the manufacturer gives on most entry level and mid to upper range gear (unless otherwise stated) is based on a full range signal sent through the supplied crossovers. You can almost always get by with sending them more power with a 60-80Hz highpass crossover as it reduces the chances of bottoming out and alleviates any thermal concerns. Good passive crossovers usually have one or more tweeter attenuation settings because you really don’t need them getting the same power as the woofer, especially when they are often mounted closer to the listener.

When running active though, do you need 200w for your tweeters if you have 200w for your mids? Nope. You have removed the resistors and shelf filters in the passive box so sending them 200w just means you’re going to use amp gains to lower them or the eq. This has been argued to death in other threads but in my experience, the higher frequencies don’t need the power to produce the same volume for the same reason your mids don’t need the same power as your subs.

I have an old school setup, the processor outputs 2v to an active crossover which can boost the signal up to 4v. The amps can only accept a max of 2.5v and as such are set to the minimum gain and I use the crossover to eek out that extra .5v before the amp clips. With 400w for 0-50Hz, 200x2 for 60-500Hz, 50x2 500-2.5KHz, and 50x2 for 2.5KHz+, the system naturally produces a decent Harman curve except I needed to lower the upper midbass slightly (300-500Hz) and tweeters are lowered a little as well. The rest just falls in line.

I will never go back to 50w for midbass after hearing what 200w sounds like…and my midbasses aren’t anything fancy, just 25 year old MB Quart QWD160 6.5”s.

 

[chuyler1]

Your welcome.

I’ve also been going through a lot of old school install features lately to see how they used to do it back in the day. Here’s a great example:

Brian Silvester - 2000 Ford Mustang GT - 2001 AS&S

Kelly, Tim "Setting the Benchmark" Auto Sound & Security July 2001: 54-63. https://live.staticflickr.com/65535/52839882742_362093f780_h.jpg https://live.staticflickr.com/65535/52840863190_d99c1166dd_h.jpg https://live.staticflickr.com/65535/52840453221_1ac1ae6e33_h.jpg...

www.caraudiojunkies.com

Two amps wired for just 3 channels, a zx500 for the subs that made 600+ watts, and a zx350 rated 100w at 4ohms and 200w at 2ohms. But look carefully at the install and you’ll spot a pair of midbasses on each side and the article mentioning some secrets in the crossover. Guaranteed they had the amp putting out 200w from 80-200Hz to the pair of 6”s on each side (wired parallel), and 100w to the 5.25” component set, with maybe some tweeter attenuation.

 

[chuyler1]

If so, 50w may be enough for good sound quality, but at what volume?

I have a 2.5watt tube amp in my living room, it’s good for just above loud speaking level with pretty good bass at that level too, but in the car, I listen much louder than that with speakers that have lower sensitivity. Road noise is often at or above speaking level and I want the music to float over that. 50w works, or I will say 85w since I had a system set up like that which I did enjoy for a long time, but it meant I had to run a 90Hz crossover point or overlap the subwoofer to get the midbass punch I was after. The speakers could have taken more, I thought it was my install but looking back it absolutely was lack of power that killed 200Hz and down which left me over working the subwoofer and pulling the sound of the bass rearward. So yeah, you can get by with 50w, but if you want up front bass, send those speakers some decent power and work through the vibrations in the door until they don’t rattle.

 

[chuyler1]

A speaker with 84dB sensitivity reaches 84dB with a single watt. Normal conversations are around 60dB. So… a handful of watts is plenty.

Road noise at highway speeds with windows closed is around 70db, windows open approaches 90db. You will barely hear 1 watt. Most of us know what 5 watts sounds like windows open and closed, it’s a factory radio. If a handful of watts is plenty, why are you even here?

You’ll get 20 watts out of a decent aftermarket radio or something like the onboard chip of the JBL MS8, many of us know what that sounds like too and it’s not enough clean power for open window driving. My MS8 is enough to over drive a 4” coaxial at full range but it won’t push a 6.5” midbass to its limit at full range.

I don’t have the technical terminology to explain it briefly but plenty of other discussions cover the fact that the way we rate amplifiers with RMS doesn’t translate to the power each driver actually sees. The typical tweeter only needs and can only handle about 10w but even hooked up to a 100w amplifier channel with the proper crossover won’t see more than 10w. The watts are needed for sustained low frequency amplitude. 50w is fine…if your crossover point is 120Hz. If you want up front bass though, you need the power to drive those speakers the way you drive a subwoofer. If you want live concert level volume out of your system (110db+) you’re gonna need 100w or more at 80Hz. You can get that from your subwoofer or you can power your midbass appropriately and keep that bass up front.

 

[chuyler1]

Personally, I use amps that are higher rated than the speaker's RMS. And simply hedge my gain settings. My rationale is like a sports car that has more horsepower than necessary but simply take it easy on the pedal. I'd rather have the power I need, and know that I do VS not having enough when I want it.

I’m pretty much the opposite, I have more fun driving a slow car fast but they sell just as many Corvettes as Miatas so to each their own.

I guess I apply that to car audio as well, but more that I stick to within maybe 10% of rated power and make sure I get close to max volume on typical listening sessions.