BAMTM impedance.

[318Shawn]

Has anyone had a problem running these on their recievers? I have a Denon AVR-1905. I will be running them in small mode with a sub.
I am also considering using one as a center channel. Off Axis doesn't seem like a issue as I will always be directly in front of it for HT and would have it off for music. Has anyone tried them as a center? I searched and there was one thread but it didn't seem like they ended up trying it.
Thanks

[Gollum]

318Shawn,

Look at your receiver manual. I think the BAMTM can be considered as a 6 ohms speaker, so it's hard to think your receiver can't handle it.

You can probably try them as center channel, but I haven't read anything on this topic too. Even if you are right in front of the center channel, don't forget the horizontal dispersion of the speaker (becomes 'vertical' for a center channel) and the early reflection on the ground. If used under the TV, you'll have to maybe tilt it up a bit to get the best response curve... as Zaph says :

"The last image linked above shows only the 15 degrees off axis curve with the tweeters to the inside, which can be considered the optimum. In that case, the response curve is nearly perfect."

Good luck !

Dino

[sreten]

Originally posted by Gollum
318Shawn,

.....I think the BAMTM can be considered as a 6 ohms speaker......

Dino

Hi, no it can't. Very 4 ohms in my book, /sreten.

[Gollum]

sreten,

How do you determine a speaker is 4/6/8 ohms ? I know that, typically, MTM gives a 4 ohms speaker. But in the BAMTM, the SEAS tweeter is 6 ohms... and when you look at the graph provided by Zaph, you can see the curve often way above 4 ohms, even above 10 ohms over 600 Hz.

Do you take the lowest point in the curve as the speker's impedance ? It's not an average at different frequencies that gives a fair idea of the impedance ?

Thanks,

Dino

[318Shawn]

The tweeter is 6 ohms but the two 8ohm drivers in parrallel show a 4ohm load which draws alot more power at lower frequencies. I would look at the lowest impedance as the rating as it fluctuates depending on the frequency it is playing. My reciever is rated at 115watts @6ohms but Says nothing about 4ohms. I read somewhere that recievers cannot be rated to 4ohms or UL will not pass it but do not know if that is the case or not. I assume alot of recivers will play it or else I don't think these speakers would be as popular if you needed seperate power amps to drive it. It would kind of defeat the purpose of a Bargain MTM if you need to spend more $ to run them.
Shawn

[sreten]

Hi,

The two bass units in parallel have Rdc = 2.7R, = a 4 ohm speaker.

Most recievers will drive 4 ohms, but not necessarily with optimum
power, especially those with IC output stages, which much prefer
8 ohm speakers in terms of effective power output.

The Denon should be fine with a 4ohm load, especially if it is
L+R only and you use 8 ohm speakers for the other channels.

The BAMTM may be cheap but it is not nasty, it deserves decent
amplification, which in my book is not IC powered cheapo stuff.

/sreten.

[critofur]

Did you end up liking the BAMTMs? I've just got the parts (some cheap at the PE tent sale!) and I'll be building some over the next two weekends Sundays.

[MisterTwister]

that's true, they sound horrible on 8ohm receiver.
some 8ohm amps can handle them well though. they sounded
very good on my harman kardon pa2200 amp.
it's rated 8 ohm, but can drive 4ohm speakers easily.

[Hezz]

318Shawn,

A lot of the modern A/V receivers have a sensing circuit that will not allow them to play anything below a 6-7 ohm load. Driving 5-7 channels with a single transformer in addition to a pair of mains dipping to 4 ohms is too much to ask of the A/V receiver unless you have an outboard amp for the mains.

[318Shawn]

Originally posted by critofur
Did you end up liking the BAMTMs? I've just got the parts (some cheap at the PE tent sale!) and I'll be building some over the next two weekends Sundays.

Sorry, haven't been on the forums for quite some time. I am happy with them I have had three of them running for the last year and a half off my Denon receiver that is 6ohm stable.