Choosing an amp for a subwoofer

[NMMark1962]

Hey all,

I know that the Focal Sub Utopia EM and Wilson's Hammer of Thor require external amplification (unlike some that include its own sub) so I was just curious to learn if the brand of amp (for the subs from Focal and Wilson) can affect the overall sound. PLEASE forgive my ignorance here, but while an amp for Lamm, DarTZeel, Krell, etc will sound different with main speakers, will the different amps affect the subwoofer's sound? Or, since the sub just performs below a certain frequency, is the brand of amp less important?? If you are using a high brand of amp for the main speakers, could one conceivably use something like a Class D amp for their high power for the subs??

If I were to have Seaton Sound build me a four woofer sub, and the subs do not have internal amping, could I use some Class D amps to power the subs??

MANY thanks,

 

[Bruce B]

I'd certainly look either at some older Krell amps or newer amps with the Hypex modules. Amps do make a difference.... even for subs!

 

[Mike Lavigne]

;

Hey all,

I know that the Focal Sub Utopia EM and Wilson's Hammer of Thor require external amplification (unlike some that include its own sub) so I was just curious to learn if the brand of amp (for the subs from Focal and Wilson) can affect the overall sound. PLEASE forgive my ignorance here, but while an amp for Lamm, DarTZeel, Krell, etc will sound different with main speakers, will the different amps affect the subwoofer's sound? Or, since the sub just performs below a certain frequency, is the brand of amp less important?? If you are using a high brand of amp for the main speakers, could one conceivably use something like a Class D amp for their high power for the subs??

If I were to have Seaton Sound build me a four woofer sub, and the subs do not have internal amping, could I use some Class D amps to power the subs??

MANY thanks,

you are going to get lots of different answers to your question based on particular perspectives.

the following is simply my perspective.

I feel that the main issue involved is ultimate coherence, followed by how deep the bass actually goes. which amp is powering the below 50hz, or below 40hz frequencies, is much less important than whether those frequencies truly completely integrate, and then what sort of headroom you have. if the bass is really well integrated, and the bass is linear thru the musical frequencies since it goes really low, then you have that ease and foundation to the music.

one big question regarding integration is how does the amp powering the deep bass compliment the character of the amp powering the mids and highs? I like Class D amplification for deep bass for a number of reasons. (1) it's very linear in the deep bass, (2) it has no color of it's own so it mimics the source amp in terms of character, (3) it is very efficient electrically and thermally so it does not unduly stress your power grid or get hot under stress, (4) small form factor so it fits in a speaker cabinet, (5) it can be purpose designed to do exactly the job it is asked to do.

in the case of the MM7 bass towers and their integrated class D amps, the real magic is in the way the two towers integrate in the bass. you do not hear any lack of coherency in the bass. the main towers do decend to below 30hz but without much weight in those frequencies allowing the bass towers to integrate properly. I do not believe that any separate subwoofer/ full range speaker can do that quite as well. so the big issue is whether the main speakers are designed to integrate, or to be full range. this is an either/or type thing, you cannot have it both ways without performance compromises to some degree.

the MM7's extend to 7hz (-3db) and 3hz (-6db). and they do it easily. and the MM7's do not require any outboard crossover compromising the mids and highs. with the MM7 the main towers run totally passive except a tweeter attenuator.

so getting back to your original question; the amp itself is secondary......it's more about how the whole system integrates. it's only after solving that problem that the actual amplifier performance becomes an issue. can a conventional topography amplifier surpass a class D amp powering only deep bass?

I've not done the comparison myself so I can only guess based on things I've heard. I have a hard time imagining any conventional amp competing with what I hear in the bass performance in my room. but that's just one man's opinion. maybe if the MM7's were set up to allow for an alternative amplification we could answer that question.

 

[NMMark1962]

Well said Mike and MY THANKS!!! Still much to learn and boy, am I learning. I know for SURE I need to get to your place to start listening. GAD, I am so excited to get this started as I cannot even begin to imagine who this will all settle out in the end.....I sure have my favorites but, I will keep my ears and mind open...more thoughts but a phone call me be better for what I am ruminating on...then again, it is too late and I need to hit the sack....

Cheers,

 

[amirm]

I have done a bunch of tests with subs: the only thing that makes a difference is the efficiency and power of the amp. For that reason, class-D amps are the way to go. Their higher efficiency allows them to extract more power from the socket, producing better bass. Whatever ails their high frequency response does not come into play with subwoofers. I have tested audiophile amps and they lose to much cheaper class D amps.

 

[rockitman]

I would worry about the correct speaker choice first. Subwoofers are there to solve a problem. You may not need them depending on your room and speaker choice.

 

[Ron Party]

If I were to have Seaton Sound build me a four woofer sub, and the subs do not have internal amping, could I use some Class D amps to power the subs??

MANY thanks,

Mark already has built precisely that and it did have internal amping. May I strongly recommend just giving Mark a telephone call?

 

[Mark Seaton]

Hey all,

I know that the Focal Sub Utopia EM and Wilson's Hammer of Thor require external amplification (unlike some that include its own sub) so I was just curious to learn if the brand of amp (for the subs from Focal and Wilson) can affect the overall sound. PLEASE forgive my ignorance here, but while an amp for Lamm, DarTZeel, Krell, etc will sound different with main speakers, will the different amps affect the subwoofer's sound? Or, since the sub just performs below a certain frequency, is the brand of amp less important?? If you are using a high brand of amp for the main speakers, could one conceivably use something like a Class D amp for their high power for the subs??

If I were to have Seaton Sound build me a four woofer sub, and the subs do not have internal amping, could I use some Class D amps to power the subs??

MANY thanks,

Hi Mark,

For subwoofer use there are a few requirements that are more important than with full range speakers. In short, maximum useful power and how long that can be delivered matters a LOT. What happens if you reach the limits of the amp vs. the design of the subwoofer is also very important if you don't want horrid sounds or drive units self destructing. While high damping is nice/desirable, it mostly makes for a modest difference which may be audible, but is also easily corrected electronically in an optimized/paired system.

Aside from high frequency behavior with different impedance loads, the most significant difference between various class D or similar amplifiers is the amount of power delivered over time. Some can only deliver their rated power for short durations and higher frequencies, and some can only deliver shorter bursts. To be fair, we do not need 24 hours or even 2 hours of continuous output. It simply never is required in playback, and a smart designer will provide greater amplifier headroom for a useful duration rather than limit the amp to 1/2 or 1/6th the available power.

 

[Steve williams]

Hi Mark

Nice to see you again over here. Are you going to RMAF this year and dinner with the group

 

[Mark Seaton]

Hi Mark

Nice to see you again over here. Are you going to RMAF this year and dinner with the group

Definitely, my flight is already booked. I hope to spend a more time around here in the future.

 

[MrAcoustat]

I would worry about the correct speaker choice first. Subwoofers are there to solve a problem. You may not need them depending on your room and speaker choice.

Man i am glad to see this response i was starting to think that i was the only one thinking like that - - - with the RIGHT speakers in the right room you don't need a sub or two or four or eight. now that's telling it like it is.

 

[treitz3]

Eh, telling it like it is would be to say that "there are not many speakers/rooms out there that would not benefit from a sub or 4".

Tom

 

[MrAcoustat]

Eh, telling it like it is would be to say that "there are not many speakers/rooms out there that would not benefit from a sub or 4".

Tom

That sir is a matter of choice, for ME no ( subs ) 30hz in my small living room is more than enough thank you., i would never tell someone not to use subs and i don't need anybody to tell me what i nedd or not, bass from a panel is very different than bass from a box that's MY opinion, live and let live

 

[RBFC]

That sir is a matter of choice, for ME no ( subs ) 30hz in my small living room is more than enough thank you., i would never tell someone not to use subs and i don't need anybody to tell me what i nedd or not, bass from a panel is very different than bass from a box that's MY opinion, live and let live

Do you have a room response graph that demonstrates the bass extension? If you're getting relatively flat to 30Hz with your panels, many of us could benefit from seeing how you set up & placed your speakers.

Lee

 

[MrAcoustat]

Do you have a room response graph that demonstrates the bass extension? If you're getting relatively flat to 30Hz with your panels, many of us could benefit from seeing how you set up & placed your speakers.

Lee

Here is my set up Lee, not perfect but whe all have to live with what whe have.

PS: Before you ask the answer is NO i did not measure i only go with Acoustat's specs.

 

[GaryProtein]

I thought this was a thread about subwoofer amps, not why we don't need subwoofers.

The mission returns. . . .

 

[MrAcoustat]

I thought this was a thread about subwoofer amps, not why we don't need subwoofers.

The mission returns. . . .

Yes you're right, let's get back to the post i'm out of here SORRY.

 

[DonH50]

For a two-channel system without room correction I would add phase control (continuous, not just a switch) to the requirement to provide high sustained power. That is critical for proper (i.e. good-sounding) system integration.

 

[FrantzM]

For a two-channel system without room correction I would add phase control (continuous, not just a switch) to the requirement to provide high sustained power. That is critical for proper (i.e. good-sounding) system integration.

That in itself would be good but it restricts very much the choise of amps IMO. This aspect of control should be left to the crossover.

Furthermore, it is important that some myths be dispelled. If one wants to know what a subwoofer does simply unplug the main speakers and play something through the subs ... a mumble would be heard with none of the nuances we, audiophiles, rave about. The reality of sub amps is as Amirm says: Power , control and headroom. Lot of these. For that Pro amps are king. Class D amps in particular are a good match because of efficiency. If we were to look at most amps in powered subwoofers we would see they are optimized for power, control and maybe efficiency. The subtleties audiophiles amps would bring to music reproduction lie up in frequency. This has not stopped some audiophiles to proudly use very expensive amps on subwoofer ... They would be very surprised that in many instances a pro amp would have done a much better job...

 

[GaryProtein]

I agree with Frantz's description.

Prospective buyers should listen to the subwoofer without the main speakers before deciding on an amplifier.

For a subwoofer almost any well made high power amplifier will do the job well.