Driving 4 ohm speakers?

[balink]

Hi guys, I was looking for some advice on driving a pair of 4 ohm speakers I picked up today at my favorite electronics wholesale chain. I've never heard of the brand before, but at $37 a pair I figured it wasn't a big deal if they were no good. The apparant construction quality won me over.

The speakers in question are MB Quart QLC104's, and according to the literature they are rated as follows:

Power Handling = 40-90 watts
Nominal Impedance = 4 ohms

I have a Sony STR-DE897 receiver, but it is rated for 100 watts at 8 ohms and I don't want to daisy-chain these speakers to create an 8 ohm load. So, what are my options for hooking these up?

 

[jayn_j]

Hi guys, I was looking for some advice on driving a pair of 4 ohm speakers I picked up today at my favorite electronics wholesale chain. I've never heard of the brand before, but at $37 a pair I figured it wasn't a big deal if they were no good. The apparant construction quality won me over.

The speakers in question are MB Quart QLC104's, and according to the literature they are rated as follows:

Power Handling = 40-90 watts
Nominal Impedance = 4 ohms

I have a Sony STR-DE897 receiver, but it is rated for 100 watts at 8 ohms and I don't want to daisy-chain these speakers to create an 8 ohm load. So, what are my options for hooking these up?

Well, MB Quarts were a reasonably well respected and popular speaker in the mid to late '90s.

By, I looked and looked, but there is absolutely nothing on impedance specs for this receiver, except for the 8 ohm refences in the users manual and spec sheet. Most modern amplifiers will drive 4 ohm speakers, and many these days are nominally 6 or 4 ohms.

On the other hand, Rockymtnhigh had an experience he reported either here or in his home theater construction thread in the display forum, where a semi-short was causing the protection circuits to kick in on a similar model Sony. You might want to PM him and ask his experience here.

Personally, I'd give it a shot. Don't go too crazy on the volume level. I think you will be happy with the speakers, if the amp will drive them.

 

[Kevinw]

4ohm are power hungry. If your A/V receiver is not capable of driving a 4 ohm speaker you could consider separate monoblock amps or a new receiver.

 

[balink]

jayn_j: I'd say the apparant external construction quality of the speakers is as good as my JBL's. Hopefully the sound will impress too. Thanks for the advice. If I hook these up and the reciever can't handle them, the worst that should happen is the reciever should go into protection mode, right? The documentation on this reciever is decidedly poor...

Kevinw: I would consider both of these options.

Any advice on what reciver(s) to look at? Currently I have Polk Audio Monitor 70's as my mains, Sony SS series surrounds and cheap sony rear surrounds and center channel. I am planning to upgrade the center channel next and the surrounds eventually. My sub is a JBL S120PII (400 watt 12" front firing). I want room to grow in my next reciever, not just handle what I already have. The Mb Quarts were tentatively slated to be rear surrounds.

As far as the monoblock amp, I have never used one before but I certainly have lots of speakers that would like to be hooked up : so I have been thinking about it. What does the wiring entail with these? What is a good choice for the MB Quarts?

 

[Paul Wozniak]

More correctly, 4 ohm speakers are current hungry. You may be able to drive them, as Jayn said. Keep an eye (Ear?) on the volume. It really comes down to whether your amps are stable at 4 ohms, and whether the MB's are a constant 4 ohms, or do they dip down lower at some point. MB Quart for $37? Quite a deal.

 

[bhelms]

I have a Sony STR series receiver (not the same model) and I can choose 4-ohm in the set-up menus. Does yours have that option? (I couldn't find it in a quick breeze through the 897 manual.) The audio section of yours specs-out very similar to mine however.

Over time I have had good (not perfect) luck with Sony Tech Support. Here's the link...

https://esupport.sony.com/US/perl/contact-email.pl?

Ask the question there. They usually answer within 24 hours.

I had MB Quart 2-way speakers installed in my truck some years back. Clear and "intense", could handle almost everything I gave them. I did add a sub, but for the higher ranges those pairs really rocked. Drove them with bridged amps providing 100 w RMS/ch if memory serves...!

jayn_j - I also reported a problem with a near-shorted speaker and that receiver. The unit would operate OK even with that short until I got to about -15dB or so of "reference", at which time the protection circuit would kick-in. You could fry an egg on the receiver at that point! I had even planned out a cooling system to help mitigate the problem. I musta damaged that speaker soon after I installed the system. What puzzles me immensely is how I didn't pick up on the problem sooner (d'uuhhh!) Once the driver was replaced everything returned to normal very quickly, no forced cooling needed, and I have never had a problem since. For most listening I can't get even close to "reference" without damaging the speakers and my ears. The receiver is at best only warm/warmer to the touch even after a forceful evening watching likes of Transformers and Ironman. Apparently it survived that short OK, but time will tell...

 

[balink]

Well the Sony doesn't like the MB Quarts as rear surrounds at all. In 2 channel mode, it will drive them but not well. I need to turn the volume up quite a bit in order to get a comfortable listening volume out of them.

bhelms: My reciever does not have a 4-ohm option. Sony tech support has not answered me yet (I inquired prior to posting here).

In regards to going with a seperate amp, it seems the sony doesn't have any pre-amp outputs (other than the subwoofer) and according to the manual, the 2nd zone output only passes analog signals. Is this typical of 2nd and 3rd zone outputs?

I am looking at possibly upgrading my reciever and getting a stereo amp or two while I am at it. Reccomendations would be appreciated. As I said before, I have lots of speakers hanging around so I can put the Sony to use powering other rooms.

Finally, can you hook up some 4 ohm and some 8 ohm speakers as a surround sound sytem on a single reciever without powering some with seperate amps? If I bought a new reciever, would I be able to find one that can utilize the MB's as rear surrounds and my other 8 ohm speakers as mains, etc. or would I have to have an all 8 ohm or all 4 ohm setup?

Thanks for the advice! Gotta love all the friendly folks around here!

 

[Kevinw]

Yamaha RXV863 Would be my recommendation for 4 ohm speakers

Yamaha RX-V863BL 7.2-Channel Home Theater Receiver (Black)
Id also consider all 4ohm
Polk LSi7 or 9s for mains

 

[jayn_j]

My vote would be for the Denon 2809 or better still the 3808 if in budget.