fernandobicho Posted November 21, 2012 Share Posted November 21, 2012 Hi I've bought a SWR GOLIATH III, but I don't know the ohm...... People say the multimeter don't give the correct measure.... What can I do? Thank you for help Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted November 21, 2012 Share Posted November 21, 2012 stick a lead in (if jack lead) take the other end of lead - measure resistance between tip and sleeve of plug with multimeter. That should work. Quote Link to comment Share on other sites More sharing options...
fernandobicho Posted November 21, 2012 Author Share Posted November 21, 2012 Thanks Find this: http://basschat.co.uk/topic/80898-checking-speaker-with-a-meter/page__p__775200__hl__measuring%20speaker%20impedance__fromsearch__1#entry77520 Quote Link to comment Share on other sites More sharing options...
Big_Stu Posted November 21, 2012 Share Posted November 21, 2012 This is the important bit from that link......... [quote name='flyfisher' timestamp='1268673982' post='775432'][i]If you just want to find out the nominal impedence of the speaker e.g. ist it 4, 8 or 15 ohms then there is a rough & ready way. Just use your multimeter to measure the DC resistance of the voice coil i.e. across the speaker terminals (with nothing else connected) and multiply the answer by 1.3. So if the DC resistance is say 6 ohms then the speaker is nominally 8 ohm impedance. [/i][/quote] Quote Link to comment Share on other sites More sharing options...
fernandobicho Posted November 21, 2012 Author Share Posted November 21, 2012 I did some measurements: [b]THE GOLIATH 4X10 = 4,3 ohm (if multiply by 1,3 = 5,59)[/b] [b]EACH DRIVER FROM GOLIATH 4X10 = 4,4 (x 1,3 = 5,72)[/b] AN AGUILAR 12'' 8 OHM CAB = 6,4 (x 1,3 = 8,32) A GAUSS DRIVER 8 OHM = 5 (x 1,3 = 6,5) A 8 OHM DRIVER = 7,2 (x 1,3 = 9,36) A 4 OHM DRIVER = 3,2 (x 1,3 = 4,16) [b]So, the question is: THE GOLIATH 4X10 IT's 4 Ohm or 8 Ohm?[/b] Thank you in advance Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted November 21, 2012 Share Posted November 21, 2012 (edited) [quote name='fernandobicho' timestamp='1353526648' post='1875698'] I did some measurements: [b]THE GOLIATH 4X10 = 4,3 ohm (if multiply by 1,3 = 5,59)[/b] [b]EACH DRIVER FROM GOLIATH 4X10 = 4,4 (x 1,3 = 5,72)[/b] AN AGUILAR 12'' 8 OHM CAB = 6,4 (x 1,3 = 8,32) A GAUSS DRIVER 8 OHM = 5 (x 1,3 = 6,5) A 8 OHM DRIVER = 7,2 (x 1,3 = 9,36) A 4 OHM DRIVER = 3,2 (x 1,3 = 4,16) [b]So, the question is: THE GOLIATH 4X10 IT's 4 Ohm or 8 Ohm?[/b] Thank you in advance [/quote]The DCR tends to be around .7 x impedance, but that's not a hard and fast rule, the range is generally from .65 to .75. Keep in mind that impedance is a nominal figure, not an exact one. Edited November 21, 2012 by Bill Fitzmaurice Quote Link to comment Share on other sites More sharing options...
fernandobicho Posted November 21, 2012 Author Share Posted November 21, 2012 Thank you........ My situation it's to link mw Eden WT-600 in bridge (8 ohm minimum) to the cab or not If it's 8 Ohm, that's ok, if not I can't use the cab with my amp in bridge... Quote Link to comment Share on other sites More sharing options...
flyfisher Posted November 21, 2012 Share Posted November 21, 2012 According to this, it's an 8 ohm cab: http://www.thomann.de/gb/swr_goliath_iii.htm Quote Link to comment Share on other sites More sharing options...
fernandobicho Posted November 21, 2012 Author Share Posted November 21, 2012 Thank you flyfisher, but SWR Goliath III exists in 4ohm and 8 ohm. That's the problem. Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted November 22, 2012 Share Posted November 22, 2012 [quote name='fernandobicho' timestamp='1353528494' post='1875727'] Thank you........ My situation it's to link mw Eden WT-600 in bridge (8 ohm minimum) to the cab or not If it's 8 Ohm, that's ok, if not I can't use the cab with my amp in bridge... [/quote]Never bridge. It's not about watts, it's about doubling voltage swing, which quadruples your chances of blowing a driver. The only exception is if you have a 16 ohm cab, which can actually make use of the higher voltage swing. Quote Link to comment Share on other sites More sharing options...
flyfisher Posted November 22, 2012 Share Posted November 22, 2012 [quote name='fernandobicho' timestamp='1353532938' post='1875826'] Thank you flyfisher, but SWR Goliath III exists in 4ohm and 8 ohm. That's the problem. [/quote] Sorry about that. I did think about the possibility but the few sites I checked didn't give the two options. Quote Link to comment Share on other sites More sharing options...
fernandobicho Posted November 22, 2012 Author Share Posted November 22, 2012 (edited) Goliath III 4x10'' bass cab: each driver of Goliath III 4x10'' a fellow, oerk, in talkbass says: [color=#000000][font=verdana, geneva, lucida,]If the measured DC resistance is greater than 4 ohm, it's almost certainly an 8 ohm speaker. Especially since the model number has an 8 as the last digit. This thread seems to back that assumption: [url="http://www.badassbassplayers.com/forum/viewtopic.php?f=38&t=7367"]http://www.badassbassplayers.com/for...hp?f=38&t=7367[/url] Most likely, the 4 ohm version had four of the BG1080C 16, all in parallel, whereas the 8 ohm version had four of the BG1080C 8, in series and parallel.[/font][/color] what do you think? Edited November 22, 2012 by fernandobicho Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted November 22, 2012 Share Posted November 22, 2012 [quote name='fernandobicho' timestamp='1353592554' post='1876372'] what do you think? [/quote]I'd call those 6 ohm drivers and a 6 ohm cab. I wouldn't be a bit suprised if SWR sold the same cab as 4 and 8 ohm, assuming that no one would bother to check. It wouldn't be the first time manufacturers have played fast and loose with the facts, nor the last. Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted November 22, 2012 Share Posted November 22, 2012 [quote name='Bill Fitzmaurice' timestamp='1353596218' post='1876414'] I'd call those 6 ohm drivers and a 6 ohm cab. I wouldn't be a bit suprised if SWR sold the same cab as 4 and 8 ohm, assuming that no one would bother to check. It wouldn't be the first time manufacturers have played fast and loose with the facts, nor the last. [/quote] I've also been trying to help Fernando with this mather and i share your idea to some extension. Maybe that's why people say that SWR speakers play louder when compared to the competition's 8 ohm cabs. One other thought about this would be that SWR could add a dummy switch for 4/8 ohm operation on the cab and no one would ever know I've been searching google for this and i'm now completely scared by the amount of people having blown PAS drivers on theis SWR cabs and in need of recone. I've found a topic on TB with a guy with an 8 ohm cab (stated on the backplate) and getting the same kind of readings from the multimeter as Fernando: [url="http://www.talkbass.com/forum/f15/goliath-iii-wiring-impedance-113123/"]http://www.talkbass.com/forum/f15/goliath-iii-wiring-impedance-113123/[/url] The plot thickens... Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted November 22, 2012 Share Posted November 22, 2012 (edited) Another thing to have in consideration: [url="http://www.talkbass.com/forum/f15/how-4-ohms-129485/"]http://www.talkbass....-4-ohms-129485/[/url] I'm a few seconds away to loose all faith in SWR/PAS gear if the same 10" drivers are being used for all models... it would be a great marketing stunt, all drivers used being the same 6ohm ones then you would get a 4x10" with 6Ohms wich would be badged as 4 or 8 ohms and a 6x10" cab that would really have 4 ohms... SWR owners, take out your multimeters and start measuring your cabs, please. We'll get to the bottom of this. Edited November 22, 2012 by Ghost_Bass Quote Link to comment Share on other sites More sharing options...
dincz Posted November 22, 2012 Share Posted November 22, 2012 (edited) [quote name='Bill Fitzmaurice' timestamp='1353554461' post='1876045'] Never bridge. It's not about watts, it's about doubling voltage swing, which quadruples your chances of blowing a driver. The only exception is if you have a 16 ohm cab, which can actually make use of the higher voltage swing. [/quote] And presumably: never buy an amp that uses a pair of bridged power modules for each output? My point being that if a speaker is being driven with, let's say, 40 volts RMS, it doesn't matter whether that 40 volts is being delivered by a single power amp channel or by 2 channels each capable of 20 volts. The speaker doesn't know or care - it's still 40 volts RMS. I don't understand this thing about bridging being a bad thing. It's simply a matter of sensibly matching the power ratings of amp and cab. Edited November 22, 2012 by dincz Quote Link to comment Share on other sites More sharing options...
Musky Posted November 22, 2012 Share Posted November 22, 2012 [quote name='dincz' timestamp='1353607778' post='1876583'] And presumably: never buy an amp that uses a pair of bridged power modules for each output? My point being that if a speaker is being driven with, let's say, 40 volts RMS, it doesn't matter whether that 40 volts is being delivered by a single power amp channel or by 2 channels each capable of 20 volts. The speaker doesn't know or care - it's still 40 volts RMS. I don't understand this thing about bridging being a bad thing. It's simply a matter of sensibly matching the power ratings of amp and cab. [/quote] You're right. If the drivers can handle a 40V swing then everything is fine and dandy. The problem is when the user doesn't really understand what's going on when an amp is bridged and uses the same load, which would in theory result in 4 times the wattage. Although I'd expect the amp to go in a puff of smoke before the speakers. Quote Link to comment Share on other sites More sharing options...
dincz Posted November 22, 2012 Share Posted November 22, 2012 (edited) [quote name='Musky' timestamp='1353613827' post='1876664'] The problem is when the user doesn't really understand what's going on [/quote] Fair point. A Bridge Too Far in that case. What prompted my previous post was the blanket instruction "never bridge". Edited November 22, 2012 by dincz Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted November 22, 2012 Share Posted November 22, 2012 (edited) [quote name='dincz' timestamp='1353607778' post='1876583'] And presumably: never buy an amp that uses a pair of bridged power modules for each output? My point being that if a speaker is being driven with, let's say, 40 volts RMS, it doesn't matter whether that 40 volts is being delivered by a single power amp channel or by 2 channels each capable of 20 volts. The speaker doesn't know or care - it's still 40 volts RMS. I don't understand this thing about bridging being a bad thing. It's simply a matter of sensibly matching the power ratings of amp and cab. [/quote]Does the amp manual state what the voltage swing is for both configurations? And does the cab manual state what the maximum displacement limited voltage swing is? If so the user can make a well informed choice as to how he should run the amp. Now try and find any amp manuals that state the former, and any cab manuals that state the latter. The product of those two figures will be [i]exactly [/i]zero. Edited November 22, 2012 by Bill Fitzmaurice Quote Link to comment Share on other sites More sharing options...
fernandobicho Posted November 23, 2012 Author Share Posted November 23, 2012 [color=#222222][font=Georgia,]PAS BG1080C 8 drivers are 8 ohm and [/font][/color][color=#222222][font=Georgia,]BG1016C 16 are 16 ohm drivers. (Information in a 2004 thread in TB, by a PAS engeneer)[/font][/color] [color=#222222][font=Georgia,]So, my cab has four [/font][/color][color=#222222][font=Georgia,]BG1080C 8... so, I believe they're four 8 ohm drivers, linked a pair in paralell and other pair in series. [/font][/color] [color=#222222][font=Georgia,]That means the cab it's a 8 ohm, I think.[/font][/color] [url="http://www.worthpoint.com/worthopedia/10-swr-goliath-speaker-bg1080c-152213157"]http://www.worthpoint.com/worthopedia/10-swr-goliath-speaker-bg1080c-152213157[/url] You're great! Thank you. Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted November 23, 2012 Share Posted November 23, 2012 [quote name='fernandobicho' timestamp='1353640712' post='1876934'] [color=#222222][font=Georgia,]PAS BG1080C 8 drivers are 8 ohm and [/font][/color][color=#222222][font=Georgia,]BG1016C 16 are 16 ohm drivers. (Information in a 2004 thread in TB, by a PAS engeneer)[/font][/color] [/quote]Quite the trusting soul you are, but as Mr. Reagan said, "Trust, but verify". PAS might claim your drivers are 8 ohm, but without an impedance chart to back up that claim it's just that, a claim. The only evidence seen so far are your DCR measurements and similar results from others, which all point to them being 6 ohm drivers. As for why PAS might be less than truthful, if they sold them as 8 ohm drivers what else would you expect them to say? Quote Link to comment Share on other sites More sharing options...
dincz Posted November 23, 2012 Share Posted November 23, 2012 [quote name='Bill Fitzmaurice' timestamp='1353626255' post='1876851'] Does the amp manual state what the voltage swing is for both configurations? And does the cab manual state what the maximum displacement limited voltage swing is? If so the user can make a well informed choice as to how he should run the amp. Now try and find any amp manuals that state the former, and any cab manuals that state the latter. The product of those two figures will be [i]exactly [/i]zero. [/quote] Sensible precautions, but the amp's voltage swing is equally important whether it's coming from a single amp/channel or a pair of bridged amps/channels. Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted November 23, 2012 Share Posted November 23, 2012 [quote name='dincz' timestamp='1353697247' post='1877667'] Sensible precautions, but the amp's voltage swing is equally important whether it's coming from a single amp/channel or a pair of bridged amps/channels. [/quote]OTOH if the voltage swing of one channel is more than adequate to drive the speaker to full output there's nothing to be gained from doubling that swing, and much to be lost, as in blown drivers. Admittedly it's a crap shoot when you don't know the voltage swing of the amp, or the displacement liimited voltage capacity of the speaker. If in doubt just assume that the cab cannot make use of more than half its power rating, and unless one channel of the amp cannot provide that don't bridge. Quote Link to comment Share on other sites More sharing options...
fernandobicho Posted November 23, 2012 Author Share Posted November 23, 2012 (edited) Maybe the speakers are 6 ohm.... maybe my Goliath III it's 6 ohm.... but works like a 8 ohm. They sell others equal like 8 ohm, as you can see by this two pictures taken today by my mate Gaspar - his own Goliath III 8 ohm: the same speakers: The Goliath III with 8 ohm label: And my similar thread in TB: [url="http://www.talkbass.com/forum/f15/whats-impedance-my-bass-cab-934721/index4.html#post13488155"]http://www.talkbass....ml#post13488155[/url] And yes, I've sended the serial to SWR, but they didn't find any information about the cab.. I hope this help someone in the future and I thank you all your help. It was a great help! Thank you! Edited November 23, 2012 by fernandobicho Quote Link to comment Share on other sites More sharing options...
fernandobicho Posted December 7, 2012 Author Share Posted December 7, 2012 Now, the recent answer of Fender. " If these were originally wired in series/parallel then this would have to be an 8 ohm cabinet total. Typically the static ohm reading on these speakers will be much lower than what they are. Best regards, Michael Roberts Consumer Relations Representative Fender Musical Instruments Corp." Quote Link to comment Share on other sites More sharing options...
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