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Surely This Cant Be Right


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Right so let me give you the low down. last night while doing a gig one of the drivers blown in a speaker.

i am currently using 2 sets of speakers one set 300w rms and and then powering a set of 100w rms from them, all of this is being powered by a behringer ep 2500.

 

The only reason i use the 100w's is that they give out nice crisp bass (well at least one of them did) so now heres my dilema, i want to replace both drivers in the 100w cabs for some 300w drivers. with me having very limited knowledge of speakers i was wondering if this would be a wise idea?

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First of all running a 100W speaker from an EP2500 is a bad idea. There is nothing wrong with some headroom and having an amplifier rated a little above that of a speaker but the spec on the EP2500 is wayyyyyyyyy to powerful for a 100W speaker, especially with the amp running into 4 ohms.

 

I wouldn't recommend replacing a 100w driver with a 300W in the same cab. A speaker cabinet isn't just a thrown together wooden box, its been designed on paper / software to enhance and work together with the driver that was specified to go into it, replacing it with something completely different which as a different spec and operating parameters is just asking for disappointment

 

Besides, I think that a 300W driver will need a bigger cabinet than that housing a 100W to operate, and possibly a different port layout / size.

 

Worst case, the additional power will probably bounce / vibrate the smaller cabinet across the stage / floor :D - you don't want your speakers turning into R2D2 and chasing your audience around the dancefloor do you? :lol:

 

Personally, I think that sound quality is something you cannot skimp on or take a gamble with. Either replace the driver with like for like, ideally the same model as the driver that failed, and buy a smaller amplifier to run these speakers from, or just buy an uprated set of speakers whose sound you like and which have a higher power handing. 100W is neither here nor there these days IMO.

Edited by McCardle

"The voice of the devil is heard in our land"

 

'War doesn't determine who is right, war determines who is left, and you wont win this war.'

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cheers for the advice guys. I've always known the amp was over rated for the speakers but coming of the 300w speakers they've never had a problem and suprised me because i was warned it wasnt a good idea but i was just nieve and ignored the advice but oh well.

 

looks like an invesment in some new cabs is the best option. would you say matching the wattage of my 300w speakers is the best and safest option?

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The ideal soluton would be to get another pair of speakers to match the bigger ones so they're all the same. (ie preferrably the same model). This way you can guarantee that each cab will draw the same power. I always feel awkward mixing different branded/sized speakers in parallel on one amp because to avoid overdriving the smaller speaker, you can only drive the bigger one at the level the smaller one is happy with...not a cost-effective situation!

 

 

.

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i know this would be the ideal situation. i am feeling ambitious though and might have a go at building my own and hope it dosent turn out another one of my other failed diy projects.

 

seen some jamo drivers 300watts each with crossovers for £60 is this a good price as i've heard jamo are a quite good?

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i've heard jamo are a quite good

 

Someone was lying to you.

 

Some of their earlier home stuff was ok, but for PA work it's junk.

 

£60 is about what you should be paying for a reasonable cheap bass driver (12" or 15"), we're talking Celestion Truvox or some Eminence, or maybe Fane but be careful of some of the studio drivers not have much excursion. I'd say the Truvox present best bang for buck at the moment (they also do some very immpressive compression drivers on the cheap). If you want a 'good' driver, you're going to need to spend £80+ each and even then you can get better but into £120+ territory.

 

Passive crossovers for a 400w rms rated cab will probably set you back £50-£60 pair. Eminence is a good bet here, and some have protection lamps to protect the HF.

 

If you fancy a DIY project then most manufacturers have plans on their website for their drivers, or one you can take and modify, or check here www.speakerplans.com and check the forum, but be warned, DIY does not neccessarily make it cheap, it just means you can get better speakers for the money you are spending. Building speakers with crap components is just a waste of time and money as they will never really do the job right. As a rough guide, if you can't afford to spend minimum £140 per cab on components (bass driver, compression driver, horn and crossover) then don't build, go and buy something instead.

Edited by norty303

DIY plans and pro audio related technical discussions

www.speakerplans.com/forum

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things just go from bad to worse. the other day i posted a question on replacing drivers because one of them gone in a speaker.

 

so yesterday i decided to have a look inside. and i was suprised to see no wires were connected to the crossover. one wire of the driver was connected to a wire of the tweeter and the other wire was also connected to the other wire of the tweeter, then a wire of each went stright to the inputs. i hope i've made this clear enough and was wondering why its wired up like this and what damage this can cause?

 

oh and one more point i did buy these second hand and in future i'll be sure to buy new ones (lesson learnt)

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What "tweeters" are they?

Are they Piezo ?

 

Piezo are normally connected in parallel with the LF driver (main speaker).

I am guessing that the original HF driver was a compression driver and has been blown, whoever repaired it, rather than replace it with a compression driver, replaced it with a cheap Piezo.

 

If the "tweeter" is still a compression driver and connected without a crossover it will blow at a reletively low volume.

 

Not having the crossover connected would not automatically damage the LF driver, as long as the LF driver wasn't over driven.

 

Jim

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its the LF driver which has blown which i dont understand because surely with the crossover being bypassed it's likely to cause the Tweeter to fail first as it'll be driven with a full range signal which will be a lot more. the tweeter still works fine and is the original

 

 

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I've merged the topics so we can keep on track.

The reason your LF driver has blown was because you have over powered it.

i was warned it wasnt a good idea but i was just nieve and ignored the advice but oh well.

 

If the tweeter hasn't blown, then either it's a piezo and not the original, hence why the x-over has been by passed or you are very lucky.

 

Jim

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Hi,

 

A mate of mine has just built a pair 15" scoop subs following the plans on the speakerplans web site (as mentioned by Norty303).

 

They sound fantastic with a very clear, thumping bass.

 

Just shows that "doing it yerself" can work.

 

Cheers,

 

Glenn.

Glenn Knights.

Mirage Moblile Disco

Wickham Market

Suffolk.

 

 

www.miragemobiledisco.co.uk

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Glad to hear they're working for him :)

 

For bass designs DIY is usually the best option until you get into really top end gear (where you then start to pay for the innovation R&D for having the next level of audio systems). That way you can spend the money on the important bit - the driver - rather than fancy boxes and marketing.

DIY plans and pro audio related technical discussions

www.speakerplans.com/forum

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Glad to hear they're working for him :)

 

For bass designs DIY is usually the best option until you get into really top end gear (where you then start to pay for the innovation R&D for having the next level of audio systems). That way you can spend the money on the important bit - the driver - rather than fancy boxes and marketing.

 

 

Hi

 

Can I assume you are Mr Speakerplans ?

 

Yes the boxes are working well for him - so much so he has built a second pair ! there is bass everywhere !

 

Thanks,

 

Glenn.

Glenn Knights.

Mirage Moblile Disco

Wickham Market

Suffolk.

 

 

www.miragemobiledisco.co.uk

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No, unfortunately I'm not Mr Speakerplans. That accolade belongs to Mr Rog Mogale who runs Void Acoustics and designs all their phenomenal cabs. I'm just the admin over there :)

DIY plans and pro audio related technical discussions

www.speakerplans.com/forum

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