Then you should have stated that in your original post. And it was negative. Yes, its your opinion, but it sounded harsh.
Anyway, to TonH, go rock that amp dude!!!!
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Turning a guitar combo into a bass combo
- Thread starter TonH
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- bass combo combo
Anyway, to TonH, go rock that amp dude!!!!
If I came across as negative I am sorry. Experimentation is the mother of invention.
Play a low E and look at the cone. If it moves half an inch or more between the extreme points you must turn volume down. If you go louder the voicecoil may hit the backplate of the magnet assembly. There are (hifi) speakers designed with open baffle principle like this but problem is the diaphragm sucks air in on one side when it pushes it out on the other. This will create an acoustic short that will almost cancell low bass. Also the stroke will increase sine there is no box that will add to the stiffness. This design might be a good compromise in an apartment situation. If you want loud an efficient bass in a rehersal or live situation though, use closed or vented enclosure.
If I recall, the Alpha 15a is used in home audio circles as an open baffle sub/woofer. Just screwed right onto a piece of plywood with a hole in it for the speaker. Sure, they use some discipline in its placement, but ultimately what he's doing isn't much different.
The combo he's got the thing in isn't exactly high powered and he's using it in low volume situations. He's got a high pass too. I think he'll be okay.
The combo he's got the thing in isn't exactly high powered and he's using it in low volume situations. He's got a high pass too. I think he'll be okay.
Well, if you're really confident the speaker will be fine all we can do is wish you good luck.
But it does seem to me it would be well worth considering a deeper (ie larger physical volume) sealed or ported cabinet with your Ibanez electrics that would give the speaker a little bit of protection. Protecting the speaker from itself is a significant function of bass cabinets. I suspect there is exactly zero relationship between the sound quality and the level of risk to the speaker and that many a system has sounded quite glorious up until the point when it suddenly didn't.
Really think you should give serious consideration to treating your amp and driver to a safer enclosure, especially as it would appear you'd have no problem in producing a nice neat job.
But it does seem to me it would be well worth considering a deeper (ie larger physical volume) sealed or ported cabinet with your Ibanez electrics that would give the speaker a little bit of protection. Protecting the speaker from itself is a significant function of bass cabinets. I suspect there is exactly zero relationship between the sound quality and the level of risk to the speaker and that many a system has sounded quite glorious up until the point when it suddenly didn't.
Really think you should give serious consideration to treating your amp and driver to a safer enclosure, especially as it would appear you'd have no problem in producing a nice neat job.
D
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The HPF at 25Hz will perform no useful function as 40Hz can easily bend your cone where no cone has ever gone before, but keeping the volume down will be good. The Eminence Alpha is a great range of speakers and I've used the 8" in a home bass cab before. You should have plenty of power handling there.
I play bass at very low volume through a 60's tube 15w Alamo Fury with a replacement 15", 225w Big Ben guitar speaker. The amp has a "bass" input jack.
Sure it kinda fuzzes out with my active 1983 Ibanez Musician bass when you dig in so I don't dig in.
Oh, I forgot to change to passive. I'll do that next time.
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Resonance (Fs) 85 Hz
An HPF set at about 90hz would do well.
Note: the pic is not my actual amp.
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It's a 15 watt guitar amp. It's fine. You can't gig with it but so what. If it sounds good it is good.
D
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Excuse me sir, I am afraid your amplifier's power switch has failed inspection. You are not allowed to turn it on. Or off, if it's already on. Don't touch that dial.
speakers aside, the main problem with a valve guitar amp is that the output transformer may be too small for bass - low frequencies saturate transformer cores much more quickly than higher frequencies, so that is part of the reason why it sounds bass-light. Keep the volume down and avoid any levels that cause audible distortion.
LOL. 25 Hz? 80 Hz might actually be of some benefit.
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You're right. We should just kick back and let natural selection take its course.
MDBass
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An HPF set that low will do almost nothing at all: it definitely won't have any effect on overexcursion.
People are just trying to help you not break this new thing you're excited about.
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Not entirely true, my 1-15 Supro Thunderbolt combo had an open back, and thumped pretty good...
About acoustic short:
A speaker in free air (not mounted) has a lot of acoustic short. When you put a speaker in a baffle/wooden panel you separate the front of the speaker from the back, hence less acoustic short. The bigger the baffle the better. When you fold over the top, bottom and sides of a baffle you create a box with open back, and the soundwaves coming from the back are more projected backwards, resulting in less acoustic short.
So what I created is an open baffle woofer, not a vented/ported cabinet and certainly not a sealed/closed cabinet. Those cabinet types are more efficient than an open baffle.
And yes placement is important with this amp, close to a wall or not, on the floor or on a stand...
As you can see on the pictures in post #1 of this thread, I placed the amp on top on another amp about 50cm from a wall. Between the wall and the amp are some plastic boxes, but no flat surface. When I sit on a chair the speaker of the amp is directly pointed at my ear so I can hear it quite well. I don't have to cranck up the volume. I can create enough volume to play along with the radio or a CD/MP3 on the stereo.
I tried it on the floor about 1m away from a wall and is sounded different, less bass, acoustic short.
The HPF that I use is variable type, so I can try different settings.
madbass6
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ok I'm not sure I understand the logic of going thru all that hassle when there are so many affordable well built practice combo bass amps out there like the Rolland micros and more! But hey if it works you and you're that bored go for it! good luck .
but keep in mind as others have mentioned already there's probably a real good reason why bass cabs are constructed a certain way with out the open back.
