HI-FI question

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HI-FI question

Postby wareika » Mon Apr 04, 2005 2:06 pm

I would like to borrow a second pair of speackers for my ampli. I can put two pairs of speackers and I think it would sound better for my birthday party...

The point is I don't want to damage the pair I will borrow. I think my amplificator is a bit too powerfull. Can anyone confirm?

I copy what is given on the amp manual. Here is ampli datas:

Power Output:
80 watts per channel, min. RMS, at 8 ohms, both channels driven from 20Hs to 20 kHz, with no more than 0.06% Total harmonic distorsion.
140 watts per channel, min. RMS, at 8 ohms, both channels driven at 1 kHz, with no more than 1% Total harmonic distorsion. (DIN)

Dynamic Power:
235 Watts at 2 ohms
160 Watts at 4 ohms
100 Watts at 8 ohms

The speackers I would like to plug in are KEF C series C 24with these datas : 100 watts / Inpedance 4 ohms.

thanx in advance.

wareika
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Postby Anonymous » Mon Apr 04, 2005 2:18 pm

Warieka

Big Five may well be able to advise as used to sell hi fi for a living.

You can sometimes find him here but more regularly over on the Trojan board.

Hope you have a great birthday and your party swings

Baldy
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Postby wareika » Mon Apr 04, 2005 2:37 pm

Thanx Baldy. Will post my question on the Trojan forum.

I also hope it will be a great party. I rent a place for the week end (9 & 10 april). Don't know if I'll play a lot reaggae cause all my friends aren't reggae fan. I think I will play only classic cause everyone enjoy tese classics more than obscure records...

Will certainly post a playlist after the party.

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Postby Big Five » Mon Apr 04, 2005 9:49 pm

You will need a splitter box under NO circumstances run both pairs of speakers from the one connection this will do damage to the speakers and amp this will over load and burn out.
The speakers your on about are Centre speaker I think, and will be no benefit, they are for home cinema use, unless they are floor standing.
Even usin’ a splitter will not make it your amp louder just more spaced in another room or the same room.

you can call me if you need more help just drop me a PM and i'll give you my number too call.
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Postby jb welda » Tue Apr 05, 2005 3:53 am

does your receiver/preamp have facilities to hook up two sets of speakers and then a selection switch to choose one or the other or both? many do...if so you can hook them up without any cause for alarm.

if not you should hook the two for each channel in series, NOT parallel. parallel would be to hook both speakers wires directly to the amp outputs. series would be to run a wire from the + pole of the amp output to the + pole of the first speaker, then from the - pole of that speaker to the + pole of the second and then the - pole of the second back to the - pole of the preamp output. then repeat with the two other speakers for the other channel. if this is unclear look up "series connection" or something similar in google and you will no doubt come across wiring diagrams. its simple really.

hooking speakers in parallel is harmful to the amplifier. series connections do not cause a problem.

all specs on the amp and speakers you quoted are open to intrepretation and therefore of only minor importance really if the connections are made properly and the speakers are not overdriven, which will be obvious from the distortion coming from them.

also DO NOT run the amplifier without speakers attached; that implies do NOT mess with the wiring with the amplifier power on!

hope that helps.

one love
jah bill
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Postby alireggae » Tue Apr 05, 2005 4:10 am

Don't link speakers as the impedance will be too low. Not so sure about Hi-Fi but in the PA/soundsystem world there is no such thing as a too powerful amp - you can run a 200W speaker quite happily with a 1000W amp. The problem is under powering your speakers which causes the amp to clip and ruin your speakers. As a rough rule of thumb your amp should be 50-100% more powerful than your speakers to allow for peaks and spikes.
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Postby Big Five » Tue Apr 05, 2005 9:10 am

if this is a standerd home amp you must use a splitter box(switching box)
http://www.superfi.co.uk/index.cfm/page ... ct_ID/1043

this one is for 4 pairs of speakers but you can get them for two pairs.
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Postby wareika » Tue Apr 05, 2005 10:49 am

Thanx for all the answers. I'll read them more carrefully cause I'm not a specialist and it's the first time I do such a thing.

Some details about my amp, to make things clearer.

My amp (Onkyo Integra / A 9711) has two pairs of plugs to put two pairs of speackers. One is name A the other B. I can select on the amp "A only", "B only" and "A+B". My Idea was to plug on A my personnal speackers (100 watts / 8 ohms) and on B the speackers I'll borrow (100 watts / 4 ohms). The point is that I think that my speackers support a more powerfull amplification than the one I'll borrow. If it is true it means than I could damage the 100 w / 4 ohms speackers by playing music too loud.

The point is that it's my personnal amp. At home I never push my amp more than 45% of its capcity for vynils and 30% of its capacity for CD playing. This max level is seriously loud enought at home (and even way too much according my girlfriend) but I will certainly use more capacity for the party...

I hope these details are clear.

wareika
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Postby Big Five » Tue Apr 05, 2005 2:12 pm

As you have A+B you can plug the second pair start in, you can have 200-watt speakers on a 50-watt amp, and a 50-watt pair of speakers on a 200-watt amp, as long as the sound is not distorted they will run fine.
The only problem you may have is one set being 4ohm the other 8 ohm the sound difference will be a lot different.
Most home amps run on 8 ohm but will take a 4 ohm but check your manual to see if
This is ok, or on the back of the amp.
If you do not have a manual then ring Richer Sounds as there are the sole importer of Onk theses days.
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Postby wareika » Tue Apr 05, 2005 2:45 pm

Thanx a lot Big Five.

Just one thing. Why do you mean by "The only problem you may have is one set being 4ohm the other 8 ohm the sound difference will be a lot different." One of the pair will play louder?

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Postby rutabowa » Tue Apr 05, 2005 2:52 pm

If it's a hifi amp there may be problems running it loud for the length of a party, no matter how the speakers are hooked up... cos they overheat easier than PAs. so a fan might be in order.
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Postby Big Five » Tue Apr 05, 2005 3:15 pm

wareika wrote:Thanx a lot Big Five.

Just one thing. Why do you mean by "The only problem you may have is one set being 4ohm the other 8 ohm the sound difference will be a lot different." One of the pair will play louder?

wareika


4ohm tend too be deeper sound, JBL's used 4 ohm a lot in the old days the base is stronger on 4.
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Postby Big Five » Tue Apr 05, 2005 3:29 pm

in layman's terms this may help.
First your garden hose (8 ohms).... your water (music) comes out but its not that much. Its going full blast and even at full blast... you will only get so much water (music) from it. You can never empty (put too much load) on the barrel (amplifier). You get what you can get. Take it even a step further... a straw (16 ohms). Same difference.

Second your firehose (4 ohms). Lets assume for the sake of arguement that your barrel (amp) can take in a firehose (4 ohm speaker).... if the amplifier can handle a 4 ohm load then that tells you that it can fill up with water faster than the firehose can take it out (in theory).

try and stick to to pairs of 8ohm speakers
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Postby wareika » Tue Apr 05, 2005 4:16 pm

Thanx. I fully understand the explaination using the water idea.

Rutabowa, yes it is a Hi Fi amp. I did think about the overheat point. I simply hope it will be fine for a party. I plan to borrow a second amp, in order to replace it in case of overheat problem. The point is I just plan to play music quite loud but not very loud. Finger crossed.

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Postby rutabowa » Tue Apr 05, 2005 4:22 pm

yeah just have a spare! i've found it tends to be the amount of time it's on more than the volume that causes overheating... it's both of course really.
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