| Cab speaker impedances [message #3694] |
Thu, 12 February 2004 22:30  |
QModer
Messages: 413
Registered: June 2003
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This might should be in another section but I'll try here first as its not really a repair problem. More of a modification thing. I know first off that Kustoms like no make that love four ohm loads. I know too that the 2x15 cabs are eight ohms. You run two of them and get the magic formula. I have a 2x12/2x10 cab and its the magic four ohms too. I have a three fifteen and its not. Its not far off but its not. Anyway what I wanna know is can I change the speakers to make it magic four ohms? Next to do that is what impedance are the speakers now? Are they 16 ohms in most Kustoms wired together to get eight ohms in each 2x15 Kustom and how are the 3x15's wired to get their odd combinations. The cab is not as loud of course as two of the 2x15's with the magic impedance match and it also seems to cause the amp head section to have to be run louder and creates a distortion in the process. Not a good situation for bass. Thanks in advance for your answers to these inquiring minds wanna know questions.
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| Re: Cab speaker impedances [message #3695 is a reply to message #3694] |
Thu, 12 February 2004 22:45  |
QModer
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I asked about the 16 ohms but they could be four ohms speakers too wired together to get the eight ohms cabs and then two of them to make the magic four ohm formula. This may be a question for our resident Kustom tech Steve but if anyone knows please chime in.
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| Re: Cab speaker impedances [message #3699 is a reply to message #3696] |
Fri, 13 February 2004 01:07 |
QModer
Messages: 413
Registered: June 2003
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Hi Don and thanks for the info.. It does read 5.6 ohms. The 2x15 is not louder by itself it takes two of em 2x15's to really wake up one. What if I replaced the third 16 ohm speaker with and eight ohm one. Would that make the old 3x15 read 4 ohms and be what the heads wanna see?
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| Re: Cab speaker impedances [message #3705 is a reply to message #3701] |
Fri, 13 February 2004 09:13 |
pleat
Messages: 1454
Registered: June 2004
Location: Belding, Mi
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Kustom, I would guess was making the most of production costs. The 3x15 cabinet was used for PA with the siren horns, they also to increase the product line, it was a natural to make a 3x15 guitar and bass cabinet, and then to increase the product line even further, offer the 3x15 cabinets with JBL's, Altec's, CTS, and Jensen speakers. They did the same with the amp heads, same power amp board, same chassis, same head cabinet, only difference were the face plates and effects for each of the five K200 heads. Back in 60's we all thought bigger was louder. I do agree that a more efficient speaker will produce more sound pressure. I would be interested if anyone has done the homework to figure the internal volume for the kustom cabinets, 115, 2x12, 3x12, 2x15, 4x10, 4x12, and the 3x15 cabinets.
Keep in mind the db level between a 4 ohm and a 8 ohm cabinet is only 3db. All in all it is best to operate a amp at its rated impedance, or larger impedance to prevent overheating or amp failure.
Don
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| Re: Cab speaker impedances [message #3708 is a reply to message #3703] |
Fri, 13 February 2004 18:42 |
QModer
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I am beginning to understand what you are saying Pleat and Steve is that the internal volume is not really enough to support 3x15's probably especially used with bass. But if I go to 2x15's should'nt I just trade it (the 3x15) off for another 2x15 as would'nt I be just hauling around the extra cab size for nothing then? On the other hand if I got one of the emience 15's in eight ohm how much of wattage rating should it carry and whats the part number?. After all the Kustom is only a hundred watt head and other two speakers would be still be carrying 25 percent of the load if I understand that right correct?. I could place the eight ohm speaker in the top since it would be carrying the largest load to have it right in your ear as sort of a monitor would that be good?.
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| Re: Cab speaker impedances [message #3709 is a reply to message #3708] |
Fri, 13 February 2004 22:38 |
BC
Messages: 583
Registered: March 2000
Location: Kentucky
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Just for the record, Kustom was not the only maker of 3x15 cabinets.....they may have been the first......but Peavey made some 3x15s also. On the subject of cabinet volume....when we all met at the Nashville guitar show in 2000, I asked Bud how he came up with the cabinet size to get such good tone......as he motioned with his hands, his reply was, "I thought they should be about this high...about this wide and this deep" Correct or not.....I should get so lucky! BC
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| Re: Cab speaker impedances [message #3713 is a reply to message #3709] |
Sat, 14 February 2004 19:46 |
QModer
Messages: 413
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Hi BC. Yes old Ross did do a good job. I knew peavy did a huge 1x18 cab but I did'nt know about the 3x15. I remember Earth doing a 3x15 though. Actually one of the reasons I did'nt like peavy was the size of their 2x15 cabs. I have only seen one 250 cab and it really did'nt really seem that bad to me in size. It would be nice to have one of those.
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| Re: Cab speaker impedances [message #3714 is a reply to message #3713] |
Sun, 15 February 2004 10:55 |
ET
Messages: 146
Registered: October 2000
Location: Charlotte NC
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wanted to jump in on the comment you made about loading the eminence in the top position.. I"ve mixed n matched, including eminence and one of the things I found was the upper section of both the 3x15 and even the 2x15s, which are narrower than the lower end, don't allow for as much cone travel and when I was really slamming the cabs (Mackie 1400) with more juice than they ever imagined from the kustom 200 heads, I would get a snap/pop sound and I thought I had a blown speaker... I moved the Emi down to the bottom position where there is the most space and the sound cleared up..both cabs were this way...now mind you, my other speakers were subwoofers too with a long throw edge, but they didn't need as much air space.. I also remember this comment coming from Andy Ross when they were making the Krossroads bass rigs...they originally used EVs and the 15 cabs were fine, but there was just not enough air space in the 2x10 versions and they had to go to another brand speaker..get your biggest guy buster down low..you can also try not plugging the top 15 speaker at all..leave it in there, just don't hook it up...the cone will move sympathetically and you'll swear its almost on...but your amp will be happy running the pair of more capable 15s and you'll still look cool with those big towering cabs...this is all stuff that local speaker reconers and guys smarter than me have suggested and we've tried a bit of all of them and gotten varying, interesting, and sometimes great results...
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| Re: Cab speaker impedances [message #3716 is a reply to message #3715] |
Sun, 15 February 2004 20:42 |
QModer
Messages: 413
Registered: June 2003
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ET seems like I remember once on one of other threads something about that big mackie making funny nosies thru one of your Kustoms although I did'nt know what made it at the time and did'nt know it was three fifteen. I'm glad it was'nt your speakers. Don your theory on this was interesting too on two eights. Do they make good eights for bass? What do all of you think about maybe replacing the top fifteen with and eight ohm ten then? Thanks again for your thoughts. Would two eigths require more air reflex space than the one fifteen or is that just in my mind? I can see where the two eights in sixteen ohms would then give me that magic four ohm equalized total number when combined with the two lower fifteens.
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| Re: Cab speaker impedances [message #3717 is a reply to message #3694] |
Mon, 16 February 2004 12:59 |
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...hey guys, got a question about impedence o.k.?...I'm replacing two worn out CTS 15"s with a couple of Eminence 15"s rated at 4 ohms each...if I wire them in series I'll get 8 ohms right?...and in parallel it would be a 2 ohm setup right?...if the CTS's were 16 ohm (and this I don't know as the magnets were painted over) and they were wired in parallel the ohm rating would be 8 ohms right?...is this how the K-200 cabs with 15's in them were set up new from the factory with 16 ohm speakers wired in parallel to get an 8 ohm rating?...I'd appreciate and feedback on this...thanks, Rick...
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| Re: Cab speaker impedances [message #3718 is a reply to message #3716] |
Mon, 16 February 2004 16:12 |
ET
Messages: 146
Registered: October 2000
Location: Charlotte NC
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yeah, long time ago I was complaining that I finally had gotten more muscle behind the amp side of things, only to have my speakers fart out...and the amazing thing was that my speaker Doc knew immediately what the problem was...and just moving the eminence from the top position to the bottom was enough to clear it up...it literally sounded like I had blown speaker and was hitting them too hard..they would "whap!" on the lower notes..yet when you pulled them from the cab, they tested fine...someone also mentioned adding longer porting or even on those 3x15s you can consider flipping the baffle, isolating the top 15 chamber and then porting it on the back so it can get some air of its own...good example of rear porting on the older Peavey TNT 2x10 cabs...to me, if you've got a 3x15..be proud of that towering beast and use the thing...so it doesn't pump quite as much db...the visual alone makes it sound louder!
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| Re: Cab speaker impedances [message #3719 is a reply to message #3717] |
Mon, 16 February 2004 20:12 |
QModer
Messages: 413
Registered: June 2003
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Rick you are absolutley right on all of your wiring assumptions. Et is that what you did to your 3x15, just took out the top speaker and put in two 8 ohms? Or did you flip it the bottom and top over speaker board over too? It would seem that going with just the two bottom two fifteens would help with the internal volume of the cab too. But a couple of eights in the top would sure help the pop too.
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| Re: Cab speaker impedances [message #3721 is a reply to message #3694] |
Mon, 16 February 2004 23:25 |
Bill
Messages: 64
Registered: March 2002
Location: Kansas
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I have a Frankestein 3x15 which has two JBL E140 bass speakers (8 ohm) and still has the horn at the top. The cab came with no ports, so I put in 8 hidden port tubes. This thing is a monster bass amp, and still has the highs with the horn. Also have a k200b with two Carvin ps15 8 ohm speakers....a completely different animal than the Frank. I even built a 5 inch extension on the back of a 2x15 cabinet which really brought out the lows! Like the others said do a little switching around and see what you like. Everyone's taste is different, but All Kustoms are KOOOOOL!
Enjoy that Kustom. We all do.
Thrill Bill
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| Re: Cab speaker impedances [message #3722 is a reply to message #3716] |
Tue, 17 February 2004 00:13 |
pleat
Messages: 1454
Registered: June 2004
Location: Belding, Mi
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Senior Member |
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My original thoughts on flipping the baffle board over, and then sealing off the internal side of the cabinet was to match the internal volume of the kustom 2x15 cabinet. It sounds like a lot of players like the sound of the 2x15 cabinet over the 3x15 for bass. The thought of adding a pair of 8" or a 10" speaker in place of where the other 15" would go was to add some snap and to try and get a 4 ohm load to the amp. Keep in mind that the smaller speakers are operating at a frequency at a predetermined crossover point. Say 2K or higher, they are intended to get some snap out of the higher frequencys only. So with the higher frequencys you don't need a super heavy duty speaker. The original siren horn could be used, just up the crossover point. Bands are miking and using direct in's to the pa which in turn are driving pa stacks with 18's,15's, and horns. ET suggested just leaving the speaker in place not wired. JBL used to do that in some of their cabinets. The dummy speaker was called a passive radiator. That would require leaving the cabinets internal structure as it is even if you decided to flip the ports to the bottom half. Yet another thought is, leave 3x15 cabinet original, place two 8 ohm speakers in the cabinet and wire it parallel for 4 ohms and send that pair to the speaker jack. Add one 4 ohm speaker in the remaining spot and wire it to another speaker jack. The pair of speakers can be driven by the k200 4 ohm amp. The single speaker can be driven by a second 100 watt slave amp. The signal for the slave amp can be tapped from the RCA jack on the back or you can add a slave amp out from the speaker output with the right resistors and wiring arrangement which I have posted on the site before. Kustom made the monitor 3 amp with the 7 band eq, that amp would be a good one to use. This arrangement makes the most sense to me. Smaller gigs the pair of 15's wired in parallel with the kustom head, leaving the single 4 ohm as a passive radiator, the bigger venues, use the same cabinet and head and add the second amp, doubles the wattage and gives you the magic 4 ohms every time.
Don
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| Re: Cab speaker impedances [message #3724 is a reply to message #3721] |
Tue, 17 February 2004 00:39 |
QModer
Messages: 413
Registered: June 2003
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Thanks Thrill Bill. You're right of course all Kustoms are cool. Did you use a cross over on the horn? This old amp is kinda famous in these parts too as it used by and earlier incarnation of the Allmans who played and practised in this area called Hour glass for two albums. The only hit off of them was called the Power of Love. It sounds nothing like the more modern song by Heuy Lewis of the same name. The old amp was never loud and I thought it was due to the head being weak for years. If I took out a speaker or added a back board for the eights these are all mods that could be easily undone with no harm to it. Does anyone have a good site for eight inch bass speakers?
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| Re: Cab speaker impedances [message #3729 is a reply to message #3696] |
Tue, 17 February 2004 16:40 |
Lucky
Messages: 4
Registered: February 2004
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So...please clarify for a guy whose head spins at just the slightest mention of electrical engineering.
If I've got a Kustom 100 head, with an 8 ohm output...and I plug it into a 3x15 cab rated at 5.6 ohms...it's not going to do any damage to the head? I've always been under the impression that you had to match stuff exactly or risk the wrath of blowing up amps.
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| Re: Cab speaker impedances [message #3733 is a reply to message #3727] |
Wed, 18 February 2004 02:17 |
QModer
Messages: 413
Registered: June 2003
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Do you got and address on a site for that parts place for the speakers? Thanks Steve. So what you think is that I should flip the board over and use the top as the bottom with the eights in the new top then?
Another idea I had was maybe replacing the two fifteens with two twelves and then the top fifteen with the two eights. Would the cab have enough internal volume for those smaller speaker areas then?
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| Re: Cab speaker impedances [message #3738 is a reply to message #3734] |
Wed, 18 February 2004 15:23 |
QModer
Messages: 413
Registered: June 2003
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Thats great that you are getting a new house Steve. Thats one of the best things you can get in life is a good homestead. I will really be looking forward to your long reply too.
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| Re: Cab speaker impedances [message #3759 is a reply to message #3694] |
Sun, 22 February 2004 22:56 |
QModer
Messages: 413
Registered: June 2003
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Hey Steve did you get moved in? Is there a formula to figuring how many square inches of internal volume room you need in a cab as compared to the square inches of speaker you'll have it in? Is it more for Bass or Keys than Guitar due to the greater reflex movement? What is the area of a 3x15 K200 compared to a 2x15 K250 for instance? Thanks all.
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| Re: Cab speaker impedances [message #3780 is a reply to message #3779] |
Fri, 27 February 2004 23:34 |
QModer
Messages: 413
Registered: June 2003
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Man this one great plan you've got here Steve. I'm gonna run this off in case the board loses it. I assume that these eigths are bass speakers. This should make it one very cool and efficient cab. How did you move turn out too? Do you like your new place?
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| Re: Cab speaker impedances [message #3867 is a reply to message #3694] |
Sun, 14 March 2004 23:39 |
QModer
Messages: 413
Registered: June 2003
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I thought I'd add this back to my orginal post instead of starting a new one. I disconnected the middle speaker in my 3x15 and hooked up just the top and bottom 15's. I'm running it with another 2x15 and its nearly the same as my other double cab setup. The nice thing about it is that you do have that top speaker in the bass players ear so that he hears himself. The speakers in all of my Kustoms distort a little on bass and I think its just the nature of the amps to do it. They are of the cts varity. We're having a jam tonight so we'll see how the new set up does in a live band sitution.
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| Re: Cab speaker impedances [message #3872 is a reply to message #3867] |
Tue, 16 March 2004 20:13 |
QModer
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The trial run was unsuccessful so far. The problem is that it was very distorted. It could be that head. I have two heads returning the Tech on Thursday. He called today. One is and A series the second is a B series. The head that is running the 3x15 now is and A series. However it does have some problems as one of the channels is bad right now. If this is'nt it I'll try two twelves or any other fifteens that are suggested as replacements. I was thinking too that it could be that when the two functioning 15 move back in that they could be making the middle fifteen push out and there fore make and out of phase pressure wave. But that natural compression might be helping. Ideas anyone. We had a great time though. I used my new Rickenbacker and the my nephew the bass player used the 3x15 and 2x15 together at first then he swithced to my other double cab 2x15 for the rest of the night.
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| Re: Cab speaker impedances [message #3879 is a reply to message #3876] |
Wed, 17 March 2004 20:50 |
QModer
Messages: 413
Registered: June 2003
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I called myself doing that when I wired it up but I might should look at it again. I should be getting my repaired amp back tomarrow and I'll see what it does with it first. If I can't find the problem then I suspose its time to remove that middle fifteen put a plate its place, Get two twelves to replace the two used fifteens or both. Any advice on which one to do first if the repaired amp head does'nt cure its distortion problems and the wiring is Ok?
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| Re: Cab speaker impedances [message #3887 is a reply to message #3885] |
Thu, 18 March 2004 15:39 |
QModer
Messages: 413
Registered: June 2003
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Hi Steve.
Even though its not hooked up right now it sounds like the middle 15" speaker will have to come out like a bad tooth. Would you recommend two speakers to replace the other two, just the top and bottom speakers. I am also using this cab with another Kustom 2x15 cab right now too. The other one seems fine.
I like that fifteen in the top of the 3x15 being by your ear. It seems that it helps me (we all take turns) or whoever is playing bass to hear themselves better without having to turn up more.
That may be this old Buggers niche and it might even sound better than a 2x15 with the additional reflex room then.
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| Re: Cab speaker impedances [message #3892 is a reply to message #3694] |
Thu, 18 March 2004 23:50 |
QModer
Messages: 413
Registered: June 2003
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Its not head related, cab, or bass related. At least not with what I've got to compare it too anyway. I have five working heads now and it does the same things in all of them. Two different basses. I also have a 2x15 cab hooked up with that set up. I have another full double cab 2x15 setting to it that I tried. This set up is in the shape of and L next to this one. So its easy to compare both setups sound.
You just don't notice the distortion as much unless you lean down there and thump that E string due to the 2x15 double cab being lower to the ground. My nephew just makes the effect more pronounced as he has a harder touch than mine.
I even A/B'ed the two amps together and listned closely. You really just notice it more in the 3x15 because that speaker is up there by your ear. Do the bigger Kustom cabs like the 250 and 500 series do this? If so size has no bearing. Is it something that more effecient speakers can solve? You folks who have better brands than just the stock CTS. I think I would replace the ones in the 3x15 if so because you can hear that top one so much better. What is the Thiele specs of the CTS speakers? Does anyone know? The CTS speakers hold on for dear life and its no point to replace them unless its really known to help.
I know this is a lot of questions but I see no need right now to remove the middle speaker, replace it with a plate, or really do any more to it until I get more input from you fellas.
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