Marantz SR7500 and LSi9 speakers.

[cd_r]

Hi guys!

I'm thinking of purchasing the marantz A/V sr7500 receiver and the pair
LSi9 PolkAudio speakers. However, according to the receiver's specification,
it is able to drive 6to8Ohm speakers and I'm afraid that the LSi9 are
4Ohm speakers. Can anyone tell me if I can damage the receiver
connecting these speakers?

Is it possible to solve this impedance problem biAmplifying the speakers?

What do you think about it?

Thanks you all!

 

[Buckeyefan 1]

Hi guys!

I'm thinking of purchasing the marantz A/V sr7500 receiver and the pair
LSi9 PolkAudio speakers. However, according to the receiver's specification,
it is able to drive 6to8Ohm speakers and I'm afraid that the LSi9 are
4Ohm speakers. Can anyone tell me if I can damage the receiver
connecting these speakers?

Is it possible to solve this impedance problem biAmplifying the speakers?

What do you think about it?

Thanks you all!

The Polks are 4 ohm, and most receivers cannot adequately drive 4 ohm loads. It depends on what type of listening you do. If you push the receiver, it may overheat and cause damage.

Most guys who purchase the LSi series go with outboard amps. They are high dollar speakers, and won't sound their best with a mid level receiver (again - depending on your listening habits).

 

[j_garcia]

Marantz will not like the 4 Ohm load, and all Marantz gear that I've seen recommends 6 Ohm minimum. If you are running just 1 pair of 4 Ohm speakers, it won't be a problem, but all of the LSis are 4 Ohm.

My speakers are very similar in spec to the LSi9s, including the 4 Ohm impedance and my 8300 struggled with them at higher volumes. It will work, but you will likely hear the strain when you turn it up. Pushing the receiver will damage your speakers before it damages the receiver.

You won't need to solve the problem by biamping, you can just run them off an external amp all together.

 

[cd_r]

Equivalent Impedance

Thanks you for your replies.

I was thinking in buying this receiver, instead of pre+amp, just because I
wanted to start in the "7.1-world" without investing a lot of money.
However, it is posible, as you said, to use it as a preAmplifier, in the
future, when I could afford buying externals amplifiers using the preouts
conexions.

But until then, I thought of Biamplifying (this receiver can) the speakers in
order to reduce de impedance (driving each way separately). As we know,
all the ways are parallel connectend, so to calculate the speaker
impedance we have to use the next formula:

1/Si = 1/W1 + 1/W2

So, it would be reasonable to think that the individual ways will have a
higher impedance than the sum.

Is it posible? Am I mistaked?

On the other hand, now I'm living in a 12m2 room and I wouldn't probably
have to force so much the amplifier.

What do you think about it?

Thank you.

 

[Buckeyefan 1]

Thanks you for your replies.

I was thinking in buying this receiver, instead of pre+amp, just because I
wanted to start in the "7.1-world" without investing a lot of money.
However, it is posible, as you said, to use it as a preAmplifier, in the
future, when I could afford buying externals amplifiers using the preouts
conexions.

But until then, I thought of Biamplifying (this receiver can) the speakers in
order to reduce de impedance (driving each way separately). As we know,
all the ways are parallel connectend, so to calculate the speaker
impedance we have to use the next formula:

1/Si = 1/W1 + 1/W2

So, it would be reasonable to think that the individual ways will have a
higher impedance than the sum.

Is it posible? Am I mistaked?

On the other hand, now I'm living in a 12m2 room and I wouldn't probably
have to force so much the amplifier.

What do you think about it?

Thank you.

It sounds like you are talking about bi-wiring, not biamping. For true biamping, you need a separate amp. You would use the front speaker outputs on the receiver to drive the top end of your LSi9's, and the separate power amp to drive the bottom end.

Very few if any on this forum recommend bi-wiring.

 

[cd_r]

No. BiAmp.

This receiver can use the rear sourround rear channels to drive one way of the main speakers. Look at the picture included.

 

[Buckeyefan 1]

This receiver can use the rear sourround rear channels to drive one way of the main speakers. Look at the picture included.

You are correct - it is a biamp mode. I wasn't aware that unit had that capability.

My Denon 3805 does the same thing. The issue is, you're still drawing off a single transformer. You won't double the power to the speaker. Receivers ratings are in two channel mode. When you add additional channels, the power output drops dramatically. My Denon goes from 120watts in two channel mode to 77watts in surround mode. You're better off purchasing a separate amp with a large heat sink and toroidal transformer.

Many guys here have tried the Denon 3805 biamp mode (as referred to here on the 3805 review) without any luck. A few then went out and purchased separate amps, and noticed a huge difference in output.

 

[corysmith01]

Hmm. Interesting. My SR8400's manual, as well as the back of the unit, looks virtually identical to the above diagram, however, it does not show this bi-amp mode as an option in my manual. Just for s*&^s and giggles, I'd like to try it on my speakers just to hear...buckeye, would happen to know if this should be fine even though it's not pointed out in the manual? Like I said, the two look virtually identical, but I don't know if somethings been included with the 7500 that allows this that the 8400 didn't have. Just curious...don't expect any real sound difference, but you never know til you try.

 

[cd_r]

Power

In fact, I don't need so much power, and I don't expect more audio quality. I only want to solve the "4Ohm" problem. And according to the 7500's manual and to my knoledgements of electronic, my idea would solve this pseudo-problem.

It's true that it wouldn't sound as good as using a pre+amp, but I think It's a good idea to come into the "7.1 world" without investing a lot of money. Probably I will be able to afford separated amps in the future, and then I will be able to use this unit as a preAmp. However, I think that the sr7500 receiver is a good choice for 700EUR and for a room of about 12m2.

But if you think that I could get a nicer equipment for the same price, I would be so gratefully to prove it.

Thanks you all.

 

[j_garcia]

As I said, if you only have the two 4 ohm speakers, it won't be too big of an issue. Any more than that and you will run the risk of clipping. The biamp feature was not available on the x400 models, that is new for the x500, and I think it is only on the 7500 and up. That's a very large room, and I think the 7500 is already insufficient to adequately fill it. Being THX Select, it is designed for 2000cf and below.

 

[Audio Bishop]

I have that exact system LSi9's and the Marantz SR7005 matched with a DSW4000 sub. The Marantz drives the LSi9's wonderfully. I bi-amped them and have listened to a wide variety of music (classical to Kraftwerk) and watched numerous high impact movies. It's been two months and no problems what-so-ever. It doesn't overheat and the sonic detail is to behold. Depth - impact - separation all are just as should be. Watching Rush R30 the professors drum solo is right on. Every strike is precisely placed on stage through the LSi9's - I know that ohm matching can be an issue. It isn't with this match. I have endorsed this combo to all my audiophile friends. Some have experienced it and sat there listening nodding their heads smiling. Say no more. - I just saw you were looking at the SR7000 so it's not exactly the same system. Just a correction on my post.

 

[j_garcia]

I have that exact system LSi9's and the Marantz SR7005 matched with a DSW4000 sub. The Marantz drives the LSi9's wonderfully. I bi-amped them and have listened to a wide variety of music (classical to Kraftwerk) and watched numerous high impact movies. It's been two months and no problems what-so-ever. It doesn't overheat and the sonic detail is to behold. Depth - impact - separation all are just as should be. Watching Rush R30 the professors drum solo is right on. Every strike is precisely placed on stage through the LSi9's - I know that ohm matching can be an issue. It isn't with this match. I have endorsed this combo to all my audiophile friends. Some have experienced it and sat there listening nodding their heads smiling. Say no more. - I just saw you were looking at the SR7000 so it's not exactly the same system. Just a correction on my post.

It really depends on your room, how loud you listen, etc... as to whether or not it will be adequate. No doubt Marantz receivers have always had pretty good amp sections. Impedance matching has little to do with it. A good amp will handle a lower impedance load, and most receiver are not adequately equiped to handle 4 Ohm loads; period. If you think they sound good on a receiver's amps, just imagine how it will sound on an amp with some real power. My receiver is 125wpc as well, and as I mentioned earlier in this thread many moons ago, my speakers are also similar in demand to the LSi9s. It isn't enough power to truly make them sing, so if you haven't heard them with more power, you simply don't know what you are missing.