#1
So my local Guitar Center has an Acoustic B800H head used for $299. On their website that same head costs $599. Along with it, there's also an Acoustic 4x10 and 1x15 it's sitting on and they are both $200 a piece (I don't know the specifics of either of those). Since I recently got a relatively large sum of money for graduation this has become extremely tempting to me. However, I also don't feel I should immediately spend the money I was given. So guys, can you tell me your experiences with this head and/or what you think of the pricing n stuff?
For how can I give the King his place of worth above all else
when I spend my time striving to place the crown upon myself?
#2
I don't know about "convincing" you. There exists a plethora of good amps out there. So much of the decision is based on personal preferences. You'll find fanboys and naysayers for any amp/cab combination you ask about.

Having said that, I think Acoustic makes good gear for the money. I use a B200H amp head and an Acoustic B115 cab for small venues. It sounds good to me and the rest of the band likes the tone.

Used B200H amp heads typically sell in the $150 price range so getting 4 times the power for 2 times the price seems like a good deal to me. However, you will actually only get the full 800 watts if you use TWO 8-ohm cabs. I think it's more like 550 watts with a single cab. 550 watts is plenty of power for most venues.

As to the cabs you mention, if the 1x15 is the Mk II model then it's rated for 450 watts and sells new for $300. The 4x10 is rated for 600 watts and sells new for $400 so it's the better deal, assuming both cabs are used and in similar condition.

However, if you're gonna use two cabs my personal opinion is that you'll get better sound if you use either two 4x10's or two 1x15's rather than mix the two.

If it was my decision, I would either buy the B800H head and the single 4x10, or buy the head and get two new Peavey Headliner 1x15 cabs. The Peavey cabs are rated for 500 watts and sell new for $250 apiece. Lay for a 15% off coupon from Musician's Friend and get the pair for $425. I like the big fat round sound that 15's give, but I daresay most bassists prefer 4x10 cabs these days.

Whether you buy the single 4x10 cab or get two Peavey 1x15's you'll have enough grunt for almost any venue you encounter with (IMHO) a very good sound. My opinion is free and well worth what it cost you.

-Bob
#3
Thanks for the reply! I was actually thinking of maybe just getting the 410 but in general the idea of a 115 and 410 seems good to me in order to get that low and the punch. I'm not entirely sure on how Ohms work though, why would two 8 ohm cabs be better? And how does 8 ohms work with a 4 ohm head?

Edit: Also one of the key factors is that I don't want to spend the money unless it's just that good of a deal.

Also, do you know anything about the Notch filter? IE, what it is and what it's shape button does?

3rd Edit lol: Wouldn't it be bad to have a cab that's only 600watts be pushed by an 800 watt amp? Wouldn't that blow the speaker?
For how can I give the King his place of worth above all else
when I spend my time striving to place the crown upon myself?
Last edited by Rawshik at Jun 9, 2013,
#4
The notch filter is used for removing a certain frequency from your sound. I think for the acoustic amps the filter sweeps from 50 to 1k hz. So if your having some feedback or too much boom in a specific room you move the notch filter to that frequency to help remove the problem.

A general rule of thumb is you want the cab wattage rating to be higher than the head. You can have it run the other way but you would run the risk of over powering the cab which could damage it so its not recommend.
#6
Quote by fudger

A general rule of thumb is you want the cab wattage rating to be higher than the head. You can have it run the other way but you would run the risk of over powering the cab which could damage it so its not recommend.


Quote by Deliriumbassist
As a rule of thumb, you want the wattages to match. If you have an amp that is too underpowered and you really crank it to clipping, that's going to cause issues as well.


It seems odd that they would have those cabs available for an 800 watt head then, no? Unless there's something to do with Ohms that I don't understand.

Quote by fudger
The notch filter is used for removing a certain frequency from your sound. I think for the acoustic amps the filter sweeps from 50 to 1k hz. So if your having some feedback or too much boom in a specific room you move the notch filter to that frequency to help remove the problem.


Do you know what the shape button does?
For how can I give the King his place of worth above all else
when I spend my time striving to place the crown upon myself?
Last edited by Rawshik at Jun 9, 2013,
#7
There's a lot more to it than wattage- you've got speaker sensitivity as well. You may have heard the term headroom. Headroom is important- it's kind of like a barrier between where you are and where the signal starts to distort. If you have a lower powered amp with less efficient speakers in a large room, you may well crank it to try and get to volume. Your normal playing may or may not lead to distortion/clipping. But as you know, dynamics are important in music, and if you really start digging in, you'll get distortion. If you have a more powerful amp/more sensitive speakers/better match, you'll find yourself not turning the volume dial up as much, but you've got gas in the tank for when you do dig in- the amp has enough clean power there to cope with when you dig in, or hit the boost pedal, or whatever. You can actually run more power into a cab- your eardrums would more often go first than the speaker.
#8
Well the point is that the head has potential to damage the speaker if I go "too loud", no? So those two cabs don't actually work with that head?
For how can I give the King his place of worth above all else
when I spend my time striving to place the crown upon myself?
#9
There won't really be a problem. To oversimplify, the higher the ohms rating (impedance) of the speakers the less power in watts the amp head will produce. The B800H head produces 550-600 watts if you use an 8-ohm cabinet setup. To get the full 800 watts you have to use a 4-ohm system.

A single 8-ohm speaker cab provides a straight 8-ohm load. The speaker ouputs on the back of the amp head are wired in parallel, not series. To figure the total load of two 8-ohm speaker cabs in parallel you have to take the reciprocal of the ohms rating of the two cabs and add them together.

So... with two 8-ohm cabs you get 1/8 + 1/8 = 2/8. This reduces to 1/4.

Then, take the reciprocal of the total and that's your total ohms load. The reciprocal of 1/4 is 4/1, or a 4 ohm load.

This odd formula is why it is counter-intuitive to view two 8-ohm cabinets chained in parallel together as producing 4 ohms. It would be completely different if the two cabs were wired in series, but the B800H head is wired in parallel so you have to use the formula I stated.

Also, you only get 800 watts when you use a 4-ohm load at max volume. With two cabs to share the load each cab gets approximately 400 watts, so the Acoustic cabs are rated properly with respect to the head.

If you use the single 4x10 at 8 ohms then that cab's rating is 600 watts and that's about the maximum that the B800H will produce with an 8-ohm load. Still good. So the Acoustic setup you're looking at you will be OK whether you use the single 8-ohm 4x10 cab, or use two 8-ohm cabs to produce a 4-ohm load.

Now, if you buy the B200H head and pair it with cabs that have lower wattage ratings then everything changes and blowing speakers becomes a real likelihood.
#10
Quote by VeloDog
If you use the single 4x10 at 8 ohms then that cab's rating is 600 watts and that's about the maximum that the B800H will produce with an 8-ohm load. Still good. So the Acoustic setup you're looking at you will be OK whether you use the single 8-ohm 4x10 cab, or use two 8-ohm cabs to produce a 4-ohm load.

Now, if you buy the B200H head and pair it with cabs that have lower wattage ratings then everything changes and blowing speakers becomes a real likelihood.


How do you determine the risk of blowing the speakers? The head will only produce 600w out of the 410 by itself, right? But if I cranked it, wouldn't there be issues with overpowering the 600w from the 800w?
For how can I give the King his place of worth above all else
when I spend my time striving to place the crown upon myself?
#11
You're over-thinking this. With the Acoustic cabs you are looking at, regardless of whether you use the single 4x10 or it paired with the 1x15 the risk of speaker damage is low as the cabs in question are within the capabilities of the B800H head.

You can't over-power the single 4x10 cab because you only get 800 watts with a 4-ohm load, and the single 4x10 cab supplies an 8-ohm load that only allows the head to provide 550-600 watts. Not an issue.

If you are putting out 600 watts from the head to the single 8-ohm 4x10 cab (which has a 600 watt rating) then you are within specs. No issue. You are unlikely to turn the volume knob all the way up because your volume would be deafening in church/nightclub/small venue settings.

If you are on stage in a large venue then you probably need to use a PA system anyway. Again, no issue.

Your ears are a very good determinant for speaker damage. Assuming you are using no external effects, as long as you crank up the volume and detect no distortion then there is likely no speaker damage going on. At the point where you can detect speaker distortion (again, with no external effects) you need to back off the volume.

Just this past Saturday I did a small gig with my B200H head and a single 1x15 cab and I had plenty of headroom. It's hard for me to imagine any venue outside of a stadium where that B800H system you are looking at would have insufficient power.

Also, with TWO 8-ohm speaker cabs you will get the full 800 watts (at max volume) but you will have TWO cabs sharing the load,so each gets approximately 400 watts apiece and that's within the specs of the two Acoustic cabs in question. No issue.

The cabinets will be fine. You just need to concentrate on whether the price is a good one for you and that the tone the Acoustic amp/cabs provide is suitable for your needs.

To me, the biggest issue would be lugging that rig around. Try picking up that 4x10 speaker cab. Sucker's gonna be heavy.
Last edited by VeloDog at Jun 10, 2013,
#12
I guess I just really don't understand the whole ohm thing. But you have been a lot of help, thank you very much! I'll probably just get the 410 unless I can talk the price down a bit.
For how can I give the King his place of worth above all else
when I spend my time striving to place the crown upon myself?
#13
Learn the ohms thing. It's not rocket science and can save you from making a bad purchasing decision on down the line.