Techie Help

[FrankieJ 0]

Hi Folks

 

Today I took delivery of my new Class D 1400 watt speaker system. Now the question I have is the guy at class d said there would be no need for a seperate crossover as the subs have them built in, is this true?.

 

The second question is can will both of my amps below be ok for my speaker set up and can someone tell me what bridging and stereo mean?

 

Speakers Spec:

 

1) RMS power: 1400W at 8 Ohms

2) Impedance: 8 Ohm

3) Sensitivity (1W, 1M): 94dB

4) Frequency response: 30Hz - 20kHz

5) Maximum SPL: 118dB

6) Nominal Coverage (H x V): 90 x 60o

7) Components: 2 x 15' bass bin

8) Built in crossover 30Hz – 150Hz

9) Connections: 'Speakon' and Jack

10) Built-in crossover and circuit protection have been integrated into the design

 

My Amps:

 

Yamaha P4500 - Rated 700w @ 4h (Stereo) & 1400 watt @ 8h (Bridged)

 

http://i12.photobucket.com/albums/a224/poundheaven/th_IMG_0596.jpg

http://i12.photobucket.com/albums/a224/poundheaven/th_IMG_0579.jpg

 

 

Below is my second amp Peavey CS1000 rated at 1500 watts:

 

http://i12.photobucket.com/albums/a224/poundheaven/th_IMG_0602.jpg

http://i12.photobucket.com/albums/a224/poundheaven/th_IMG_0601.jpg

http://i12.photobucket.com/albums/a224/poundheaven/th_IMG_0600.jpg

 

 

Thanks for your help guys.

[TonyB 0]

Hi Folks

 

Today I took delivery of my new Class D 1400 watt speaker system. Now the question I have is the guy at class d said there would be no need for a seperate crossover as the subs have them built in, is this true?.

 

The second question is can will both of my amps below be ok for my speaker set up and can someone tell me what bridging and stereo mean?

 

 

In a way they are correct if you run the whole system from one amp. Speaker output from the amp would go to the subs and then a speaker lead from the subs to the tops.

 

If you want to use two amps then it would be best to have an active crossover although you could daisy chain the amps - go from mixer to input on one amp then a line level lead from that amp to the other amp but it would mean both are getting a full frequency signal and might not sound that great.

 

Bridged is where the output of the two stereo channels is added together to make one mono channel of higher wattage. Unless you want to run one speaker from the amp, it is probably best not to use bridge mode. Because the two 8 ohm channels are joined together, the amp would see a 8 ohm speaker as 4 ohms. Add two 8 ohm speakers and the amp would see them as 2 ohms which a lot of amps can't handle continuously.

 

If it is the class D system I am thinking of, each speaker is 350w at 8 ohms.

[Andy Westcott 0]

94dB sensitivity is pretty poor in my opinion - how come so low?

 

That'll soak up the watts, that will!

[norty303 0]

Yep, if i was throwing 600w at a mid top cab i'd want much more than 118db out of it.

[TonyB 0]

I have been reading another thread elsewhere where someone has the same class D system which he is running with two amps with an output of about 450w per channel for the tops and 600w for the bass bins. His question was why isn't the system very loud and why do the amps keep clipping!

[DJ Marky Marc 0]

Because the two 8 ohm channels are joined together, the amp would see a 8 ohm speaker as 4 ohms. Add two 8 ohm speakers and the amp would see them as 2 ohms which a lot of amps can't handle continuously.

 

Not true....

 

When bridged the amp does not see a change in speaker ohms... they are what they are...

 

both 8 ohm speakers on bridged amp would still be 4 ohms...

 

ass bins. His question was why isn't the system very loud and why do the amps keep clipping!

 

Because no mater what Class D tell you, you will never get these speakers to do more...

 

a combination of poorly matched amps and speakers.

 

budget amps with low quality speakers

 

what ever you want to call it, it wil never be more than average..

 

this kit has its place in the market but you guys are asking more from it than its able to give..

 

there is far too much focus on the price but no one seems to read past the watts RMS in the spec.

 

 

[TonyB 0]

Not true....

 

When bridged the amp does not see a change in speaker ohms... they are what they are...

 

both 8 ohm speakers on bridged amp would still be 4 ohms...

 

 

I perhaps explained that a bit simplistically. If you use an amp bridged, the impedance is split between the two channels so at 8 ohms, each channel will be 4 ohms. At 4 ohms each channel will be 2 ohms.

 

The channels combined will be 8 and 4 ohms respectively but the way bridging works, it is split equally between each channel.

 

[FrankieJ 0]

I have been reading another thread elsewhere where someone has the same class D system which he is running with two amps with an output of about 450w per channel for the tops and 600w for the bass bins. His question was why isn't the system very loud and why do the amps keep clipping!

 

Thanks for the feedback guys, so looks like my amps are fine I just need to look at an active crossover correct??? And could I run my yamaha amp with the whole system for now?

 

As for loudness I have to say the speakers I just purchased are verrrrry loud and wasnt looking for a concert style rig just wanted a new system with a bit more bass and punch behind it. I now have my RCf Art 300's for smaller jobs. :Thumbup:

[TonyB 0]

Thanks for the feedback guys, so looks like my amps are fine I just need to look at an active crossover correct??? And could I run my yamaha amp with the whole system for now?

 

As for loudness I have to say the speakers I just purchased are verrrrry loud and wasnt looking for a concert style rig just wanted a new system with a bit more bass and punch behind it. I now have my RCf Art 300's for smaller jobs. :Thumbup:

 

Yes it will be okay to run the whole system with the Yamaha amp. If you are looking to get an active crossover, the Behringer CX2310 is pretty popular.

[FrankieJ 0]

Thanks Tony.

[Andy Westcott 0]

Ummm...

Regarding the bridge/impedance debate, two 8 ohm speakers in parallel will have an effective impedance of 4 ohms. All good so far.

 

If you bridge a pair of amps into that 4 ohm impedance, each amp will then supply current as if it were operating into a 2 ohm impedance - as far as the amp is concerned, it is a 2 ohm load.

 

This is due (in layman's terms} of the 'extra push' given by the other bridged channel.

 

Ohm's law? Bridging produces double the output voltage, leading to double the current into a given impedance. Hardly any of the budget or mid-priced amps will operate with long term reliability into such a low impedance.

 

There. I feel better now. smile icon

[TonyB 0]

 

There. I feel better now. smile icon

 

Phew, glad about that - me too smile icon

[danger mouse 0]

Phew, glad about that - me too smile icon

so could i run 2x 8 ohm speakers in bridge mode daisy channning them. my amp is a c-marks2450?

[norty303 0]

I believe the C-Marks are only rated for a minimum of 4ohm loads per channel, meaning that the biggest load you can attach in bridge mode is 8ohms. By connecting the 2 8ohm speakers in parallel you make a 4ohm load which could kill your amp as each channel effectively 'sees' a 2ohm load. If your amp is rated for 2ohm loads then you are good to run it bridged on the pair.

[Welsh Audio Man 21 0]

so could i run 2x 8 ohm speakers in bridge mode daisy channning them. my amp is a c-marks2450?

 

I run one of these in stereo. A pair of 300w RMS 8 ohm speakers. Have also run 4 speakers of it, making the load 4 ohms. 2 speakers per channel.

 

from what ive heard, its not good to run in bridged mode continuously... maybe im wrong.

 

I think the overall load has got to be 8 ohm, for the amp to be running at 8 ohm in bridged. So if your speakers are 8 ohm each, that would become 4ohm? correct me if im wrong oh technical ones! :nbow:

 

ok, norty303 has answered it before me! :Thumbup: