Bass speakers

TamDBTamDB Frets: 6
edited November 2014 in Bass
Hi all, yet another question, (i`m beginning to sound like a bloody 4 year old). I just got hold of an Ampeg PF 350 head, this cute little monster puts out 250w @ 8ohm, and 350w @ 4ohm, and now i`ve realised that I may not have any properly compatible speakers, so I thought it made sense to ask some people who know a lot more about these things than I do :)
So, what I DO have is an old car type sub rated at 300 to 600w @ 4ohm, which sounded OK when I tried it out to make sure it worked. Then there are two separate bass cabs, 1 X 12, and 1 X 15 at 100w and 8ohm each, OR two old-ish Eminence bass speakers rated at 150w and 4ohm each, one of which needs repaired.
Seeing as this amp is not going to go above quiet house type volume for quite some time, I was wondering if I  could get away with using the 1 X 12 at home, and get the Eminence repaired so I can put together a 2 X 12 300w cab for future reference.
Any and all assistance gratefully accepted, cheers T.
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Comments

  • Roughly speaking, wattage ratings mean absolutely nothing. There is a school of thought that suggests you can disregard them for comparison purposes as long as you listen for and avoid any distortion.

    Mixing speaker sizes and types is a crapshoot, try it out but the REALLY important thing is to ensure the impedance doesn't drop below 4ohms.

    Out of all the potential setups you have I wokld start with the two 100w cabs, see which you prefer and then work out if having them both sounds better or worse and whether the extra volume is useful.

    Cheers
    James
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  • martmart Frets: 3335
    At house volume the 100W 1x12 will almost certainly be fine. But as LooseMoose says, listen out for distortion. So long as there is none, the speaker is ok. And, worst case scenario, you blow the speaker, learn your lesson, and replace the driver for not very much money.

    In any gig situation, I'd be very nervous about using a speaker rated at just 100W for bass, but at home it should be fine.
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  • TamDBTamDB Frets: 6
    edited November 2014
    Thanks for the replies James and Mart, reading from that, I should be able to get away with the 1 X 12 @ 8ohm for messing about in the house, as opposed to the 1 X 15 which is a big sod to have stuck in the middle of the living room  :), and i`ll get the Eminence sorted and make up a 2 X 12 as and when. Cheers, T.
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  • martmart Frets: 3335
    Yep, just make sure when you make your 2x12 that you wire the two speakers in series to make an 8ohm load, not in parallel as the consequent 2ohm load might well kill your amp.
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  • ICBMICBM Frets: 39090
    From what you have available...

    1 - you can't trust the car speaker at all. Car audio ratings are wildly optimistic, and a "300W" car speaker could be as low as about 75W in musical instrument amp terms. (Forget the 600W rating entirely, that's likely to be "peak music power" AKA "total bullshit marketing power".) At low volume you'll still get away with it, but it probably won't sound very good for bass guitar even if you don't blow it - they're usually dull-sounding. They are usually not that sensitive either, so there is actually more risk of turning the amp up further to compensate and then blowing it.

    2 - the two 8-ohm cabs should be fine at low volume, either singly or together. Although the amp is capable of blowing them if you turn it up, 100W is quite a lot of volume for home practice even with bass.

    3 - the same applies to the 150W 12". It's probably the best speaker you have, so I might be inclined to put that in the 1x12" for now, although you can't then run it at the same time as the 1x15" since the total load will be below 4 ohms.

    4 - putting the two 150W 4-ohm drivers in series to give an 8-ohm 300W cab is the best bet in the long run, unless you want to buy new speakers. But that might be the best option, since unless the speaker only needs a small repair it may be cheaper to by a new one, they're not actually that expensive.

    In the end it may just be as cheap - and sound better - to buy a proper bass cab rated for 300W/8 ohm or 400W/4 ohm.
    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson
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  • TamDBTamDB Frets: 6
    edited November 2014
    I`m taking this all in guys. Mart: I had the series / parallel thing loosely under control, but thanks for the reminder. 
    ICBM: the car sub is going on e-bay if I can`t find any use for it, and I hear you on all of the other points, the 150w which needs repaired, only needs the paper cone stuck back on to the frame as far as I can see, but i`ll take some advice on that, and as you say, if it`s going to be silly money to sort it out i`ll check out the prices for some new ones.
    Thanks for all the advice guys, cheers, Tam  :D
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  • TamDBTamDB Frets: 6
    I thought i`d got lucky yesterday, whilst rummaging in my storage room, I came across 2 BNIB 16ohm Eminence Beta 12Bs, I thought i`d won the lottery ! (it doesn`t take much to get me going  :D ).
    Anyway, I put them straight into a cab I have and wired them up for 8ohm and fired up the amp, to hear ---absolutely NOTHING. Not as much as a fart out of these things, so i`ve had them out again, looked over every inch of them and can see nothing wrong with them, so I put my multi-meter / circuit tester on them and still nothing, no beep from the tester and no reading on the meter.
    So now i`m completely stumped, these things look the part, there`s not a mark on them, but I can`t make them make a noise, (of any kind), at this point any suggestions would be most appreciated, cheers, Tam.
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  • CirrusCirrus Frets: 4387
    edited December 2014
    If you very gently and evenly apply pressure to the cone can you get it to move? It might be they were so totally overdriven that the voice coils melted and fused!
    Captain Horizon (my old band);
    Very (!) Occasional Blog
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  • TamDBTamDB Frets: 6
    The cone, (the paper cone with the dust cap in the middle), seems to move OK, and I`m pretty sure these havn`t been used at all, as I say, there`s not a mark on them, and no solder on the tags, or any obvious marks or damage from where someone might have used female connectors. I also had a look at the little wires that go from the solder tags to the paper cone, and they seem to be fine as well. 
    I could put up some pics, but I don`t think it would help  :-S
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  • ICBMICBM Frets: 39090
    If they're Eminences, look where the cone braids come through the metal terminals - do they then go into a pair of crimped jaws at the top of the terminal? If so, solder them up - making sure you get a good 'wet' onto the braid itself - I've come across a *lot* of Eminences with contact problems at these points, particularly older ones that have been stored.

    You can easily check it before you try soldering them if you put the meter probes directly onto the cone braids underneath - be careful, you need to put enough pressure on to make contact but not enough to damage them! If you get a reading from the braids but not the terminals, that's it. I've come across this so many times that I now solder the crimps on *all* Eminence speakers I come across, whether they've failed or not.
    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson
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  • TamDBTamDB Frets: 6
    ICBM i`ve just had a go at putting the meter on the cone braids, and got nothing, so I tried soldering them anyway, the solder didn`t want to stick, so looked closer and found there is some kind of silicone like stuff all over the crimp and the hole the braid comes through, so I cleared that out and eventually got the solder to stick but still no reading on the meter.
    I``m off to make my dinner now, after which I may just go looking for a large hammer :x.
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  • ICBMICBM Frets: 39090
    They're definitely blown then. Someone must have replaced them and put the old ones back in the boxes.

    Barely even worth re-coning either, new ones are cheap enough there's no point really.
    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson
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  • TamDBTamDB Frets: 6
    edited December 2014
    That`s my main moan, these things LOOK brand new. Oh well, thanks for the advice anyway, cheers, T.


    P.S. I couldn`t find my bloody hammer  :x
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