AutoTuba build. This is the last time...

[Tom Smit]

And about turning up the gain on the amp, when playing heavy bass tunes, it's hard to measure peak voltage because of the rapid change in LF levels. But, if I play sine waves, I can get a constant reading. The problem there is that when I play sine waves at 40, 45, 50 hz, etc, it is very loud in the car at only 5-6 volts. I wouldn't know when I would be maxing out. If I set my gain to get 10 volts with a 50hz sine wave, I'm sure my music would hit peaks even higher than that and then I would be afraid of over excursion... It just seems like a loose loose situation, lol.

The meter will bounce around. Watch the meter for half a minute in-between moments of adjusting. I make sure, just for myself, that the peaks of the music don't go above 22v (but it has seen 30v a few times).

[digital_chris]

Thanks for your input, that's pretty much what I do anyway. I have had a few songs that aren't super loud but at the beginning of a bass hit, I saw over 20 volts. Most of the stuff I tested hit between 10-15 volts, some close to 20 but not much. Why do you consider 22 your magic number?

[Tom Smit]

Why do you consider 22 your magic number?

It's the max that Bill said that the MCM 8 will take.

[loudsubz]

Why do you consider 22 your magic number?

It's the max that Bill said that the MCM 8 will take.

One of the methods for finding power is:

P = E ^2 / R

so P = 22 ^2 / 4

P = ~ 121 watts

So 22 v would be the magic number

[digital_chris]

Why do you consider 22 your magic number?

It's the max that Bill said that the MCM 8 will take.

Ah, ok. I must have missed that somewhere. Thanks : )

EDIT: I just went out to test the AT with some music to see what my peaks are at now that I know 22 is my max. This is just not going to work, with my meter anyway. I just realized that any signal that goes to my Fluke peaks high at first and then settles down to actual voltage. So, when I play sine waves, it's fine because there's plenty time for it to settle, but with music, it doesn't have the time it needs to give me a accurate reading at the bass hits. I don't know why I didn't think of this earlier. Even with the faux "peak" on the notes, I'm hitting between 10-15 votls on loud tracks. The actual voltage is probably quite lower. I guess my next way to test would be with either a newer Fluke or an O-Scope, any thoughts?

[Tom Smit]

[quote="digital_chris I guess my next way to test would be with either a newer Fluke or an O-Scope, any thoughts?[/quote]
Okay, I'll be honest. I just use a regular multimeter, not RMS.
Is your AT loud enough yet?

[digital_chris]

It is pretty loud, especially for an 8. I guess I just want to find it's limit so I can stop wondering how far I can push it, not because I will NEED to but just in case I want to : )

[DJPhatman]

It is pretty loud, especially for an 8. I guess I just want to find it's limit so I can stop wondering how far I can push it, not because I will NEED to but just in case I want to : )

Instead of pushing 1 to the limit, and risking the driver, why not just build a mate for it, and enjoy +6dB goodness? Or, build a 28-36" wide dual loaded AT?

MUAHAHAHAHAHAHAHAHAHAHA!

[digital_chris]

I don't want to push it to it's limit so I can do that constantly, I just want to know where it's limit is, otherwise it will bother me. Plus, if I need to show a buddy what an 8 inch $35 driver can sound like, I would like to be able to boast it's full potential

Second, I don't have the room for 2 of these or even a dual loaded cab. I think I might try the wider version (17") though to squeeze out more low end, possibly even the 19" with a ten inch driver. Would I get even MORE low end with a ten? That would be niceee : )

[Tom Smit]

IITP

[loudsubz]

Build another.

after building my first AT, and testing it I found it to be pretty decent, and was enjoyable but no monster. After finishing my second and adding it into the mix its a whole nother ball game. It gets pretty serious after adding 2, its not the same animal.

[digital_chris]

IITP

I'm not sure what that means...

Build another.

after building my first AT, and testing it I found it to be pretty decent, and was enjoyable but no monster. After finishing my second and adding it into the mix its a whole nother ball game. It gets pretty serious after adding 2, its not the same animal.

As I just mentioned, I don't have the room for 2, I'm fitting this into a '00 Impreza.

[Tom Smit]

It's In The Plans

[DJPhatman]

Second, I don't have the room for 2 of these or even a dual loaded cab. I think I might try the wider version (17") though to squeeze out more low end, possibly even the 19" with a ten inch driver. Would I get even MORE low end with a ten?

A dual loaded TangBand W8-720 AT can be 18" internal, 19" external. You will gain +6dB over the single driver AT of the same width. (+3dB for halving the impedance, and +3dB for doubling the Vd).

You gain nothing from a 10" driver. When the HL10C, which was the king of 10" pro subwoofers, was around, Bill wrote in the plans that it works no better than the cheaper 8" MCM!