Watts. How many does one need?

[Audiotfoot]

My listening room is 13 x 14 x 8. Speakers are Polk Monitor 70's.and a pair of what used to be Marantz 7MKII. My amp is deceased and a new one is being researched with the goal of finding a respectable $500 - $600 item. There are several that are rated as tops in that price range with anywhere from 40W / channel to 100W / channel.

I want something that will give good bass response - think of the opening of Strauss' Also Sprach Zarathustra or Beethoven's Toccata and Fuge in D Minor. Or, Donna Summer's I Feel Love. Or the cellos in Pachelbel's Kanon in D.

So, is this a case of bigger is better? Or is there any need to go above 40 watts.

 

[cubdog]

What amps are you considering? Also, how efficient are your Polks? Remember with the right speakers in the right room 1 watt can be enough. Not in your case but this answer does answer your question.

 

[Bodyblue]

For 182 sq ft and with the Polks 90db sensitive 40 watts would be a good place to start.

 

[c5corvette]

Become a AK member for $25 and you will have Barter Town access to many fine amps in your price range.

 

[cubdog]

For 182 sq ft and with the Polks 90db sensitive 40 watts would be a good place to start.

Agreed. I didn't know the Polk's db rating but 40 wpc is plenty of power to wake them up.

BTW Bodyblue, I must ask. Are you familiar with the movie entitled The Bobo? If so, you'll understand why I ask.

 

[Bodyblue]

Agreed. I didn't know the Polk's db rating but 40 wpc is plenty of power to wake them up.

BTW Bodyblue, I must ask. Are you familiar with the movie entitled The Bobo? If so, you'll understand why I ask.

It is a Peter Sellers movie that is all I know. My screen name is a mash up of passwords and screen names from 20 years ago.

 

[Ken Boyd]

I use a 40 watt tube amp with a pair of power hungry Infinity's and find it plenty powerful. I listen to a lot of Classical music.

 

[4-2-7]

Polk Audio Monitor 70

• sold individually
• video-shielded
• bass-reflex design
• frequency response 40-24,000 Hz (-3dB)
• 8-ohm impedance
• sensitivity 90 dB
• handles up to 275 watts
• dual 5-way binding post terminals
• black oak vinyl finish
• 8-7/8"W x 43-1/4"H x 15-3/4"D
• warranty: 5 years

Marantz 7 MkII


Loudspeakers with 220W power handling.

Frequency response: 35Hz - 20kHz.

Woofer’s dimension: 305mm, tweeter: 45mm.

Loudspeaker’s efficiency: 88dB.

Nominal impedance: 8 ohms.

Crossover frequency: 0.8, 2.5kHz.

Possible to choose one of two frequency mode.

Dimensions (W x H x D, mm): 375 x 648 x 292.

and a pair of what used to be Marantz 7MKII. My amp is deceased

What happened to the other amp and speakers, did you blow them up Clipping?

I want something that will give good bass response - think of the opening of Strauss' Also Sprach Zarathustra or Beethoven's Toccata and Fuge in D Minor. Or, Donna Summer's I Feel Love. Or the cellos in Pachelbel's Kanon in D.

So, is this a case of bigger is better? Or is there any need to go above 40 watts.

Read what the speaker is rated for. Your much better off not clipping the Transient peaks in music, especially in classical. Having more power than the rated speaker give you head room to cover all the peaks in the music without clipping and the extra power will improve the bass response since the woofers are what suck up the power.

 

[N8Nagel]

Was just having this discussion. My "good" system's amplifier is a HK 770 (50 WPC I think?) I was mulling over the possibility of fixing the one HK 775 monoblock that I have and tracking down another mate to double my power. But the system sounds good in the small room that it's in.

On the flip side, there's some people out there that would take the same system and slap in a Phase Linear 400 or an old Crown pro amp because headroom.

I honestly can't say who's right. I've never gone down the Big Power road.

 

[Gibsonian]

No single answer can fit all here. 40 could be all you'll need or you might want more. For my search in your case quality is 1, power 2. Safer if you can find high quality 100 watts. For me 40 watts works ok for 75% of listening but not for the remainder.

 

[Bodyblue]

In such a small space with a 90db speaker 40 watts is plenty. Even at 88db and 40 watts that will still be plenty of volume for such a small room. I have Imperial 6s and really like them, but I dont care for the 7 series at all so I would go use the Polks which are very nice speakers.

 

[prisoners]

In one system I have a very nice Dynaco Stereo 70 pushing a pair of Monitor Audio Silver S2 two way speakers. The other system is in my sig. (That Sunfire is appx 200 wpc, and I use four channels to biamp the speakers..so 400 per side).

For kicks I put the 35 watt Dynaco in place of the monster Sunfire. It did not stay long. There was a distinct lake of scale, weight, and authority that the big amp had plenty of. OTOH the Dynaco sounds beautiful in the smaller room with the less demanding speakers. The lesson here is system matching and room dimensions are more important than sheer numbers.

 

[whoaru99]

If an average level of 84-94dB with peak up to ~104dB will be enough then so should be 40wpc.

If that ain't enough SPL then 40wpc ain't enough power.

 

[petehall347]

its the speakers that draw the current which = watts . nothing to do with vol really .
example . 1 watt in headphones . then 1 watt in efficient large speakers . see what sounds louder at 10 feet away .

 

[KLH9]

30 - 40 for music.

Another 250 - 500 for "head room"

 

[Bodyblue]

My Marantz 222B driving my Imperial 6s (95db) in about the same size room as the OP's will make one's fillings shake at about the 12 position on the volume knob. Could I push them into clipping? Probably easily if I wanted to but that level would be waaaaay over comfortable listening levels so why would I?

 

[N8Nagel]

speakers do make a difference. My speakers are Rectilinear III lowboys; I don't have efficiency numbers for them but they are ported and large, which is usually a sign that they're efficient. The watts needed for, say, some Klipschorns is much lower than that required for some AR3s.

Sadly, I'm not in the position where I can really do window rattling system tests, but 50 WPC seems to do me fine. I'd love to try bigger power, and in fact at one point I was running a Luxman R-1120 (120WPC) before it lost a channel, but it's "adequate" as Rolls-Royce would say. However, if you were trying to achieve reference levels with acoustic suspension speakers you may need more power.

I actually had a pair of Monitor 70s at one point and I want to say they were 91dB/1W/1m so pretty efficient. Power is nice with those but not paramount.

Got rid of them primarily because the Design Department thought that they were ugly compared to my KLH Twenty Threes. (there's a reason I keep her around <G>)

 

[Erik Tracy]

Depends.

Room size, speaker efficiency, distance to listening position, music dynamics, and personal preference.

You want to scare the neighbors in a big room, inefficient speakers sitting 10ft or more back from the speakers? Power.

Power is your friend - do not underestimate that.

Everyone quotes efficiency, 3db is doubling of power, twice the loudness is 10 times the power, etc - but they don't account for db loss based on room size and distance to listening spot.

Fried tweeters are pain. Been there - done that.

 

[petehall347]

i find a compressor limiter helps a lot in large volume areas . more for p.a work though .

 

[whoaru99]

its the speakers that draw the current which = watts . nothing to do with vol really .
example . 1 watt in headphones . then 1 watt in efficient large speakers . see what sounds louder at 10 feet away .

Dunno what you're getting at here, but the comparison doesn't seem to make any sense.