What Amplifier parameters are important for "tight bass"?

[Casey Leedom]

So I've heard that one should looks for Power, Damping Factor and Slew Rate in order to grossly characterize one amplifier or another as having the fundamental basic characteristics for "tight, well-controlled bass". I've also heard commentary on "Push-Pull" amplifiers, being able to stop a woofer's motion, etc. with regard to this. And I'm sure there are tons of other basic amplifier parameters, various feedback schemes, etc. which add up to an amplifier being able to deliver "tight bass". But I've never found a "definitive" description.

Anyone want to take a pass at this? Just curious.

Casey

[drtrey3]

Transistors.

Trey

[garbulky]

Oh that's easy: XPA-1 gen 2. There ya go!!

[Gary Cook]

Obviously the power supply is also important, it needs a sufficient combination of transformers and capacitors to hand the transient power demands. In summary, the answer is everything in a power amplifier is important.


Cheers
Gary

[KeithL]

You've got sort of a mix of fact, folk wisdom, and old school information there.....

I'll start by saying that the speaker and the room have a lot to do with your bass response, some speakers are more affected by the characteristics of the amplifier than others, and some speakers are going to give you tight bass, or sloppy bass, no matter what you connect them to. That said, the single most important factor for getting tight bass, other than the speakers themselves, is damping factor (this is the ability of the amplifier to control the motion of the woofer by sinking the current generated by back EMF). A damping factor of 100 or higher is considered to be "very high", and is what you want  (damping factors can be as high as 1000, but anything over about 100 really won't make much difference). Virtually all modern solid state amplifiers have a damping factor that is far in excess of 100 (ours are all 500 or higher), so any modern solid state amp is fine this regard. Tube amps tend to have very LOW damping factors, usually between 1 or 2 and about 10, which is why they often DON'T deliver tight bass unless you're using them with a speaker specifically designed to go with a tube amp. (Speakers designed to work well with tube amps have their own internal damping and don't expect the amplifier to provide it for them.)

An amplifier with more power is generally going to be more able to "get the speaker to do what it wants" but, strictly speaking, even a low powered amplifier with a very high damping factor should make tight bass - as long as you play it within its power limits. All of the other things you mention really aren't related to tight bass - except as they relate to damping factor. Most amplifiers with a lot of feedback have a very high damping factor. Although they aren't directly related, most amplifiers that sound good, and use a lot of feedback, also have a high slew rate. However, as long as the amplifier has a relatively high damping factor, those other two don't really matter in this context.

Push-pull is generally used in the context of tube amps. A push-pull tube amp usually has a lower output impedance than a single-ended one, which leads to - you guessed it - a higher damping factor (probably still 8 or 10 for a tube amp - which is at least better than 2 or 3). Likewise, some older solid state amps were capacitor coupled, or transformer coupled, which gave them low damping factors - similar to those you got from tube amps. Again, however, virtually all modern solid state amplifiers, including all of ours, are going to be direct coupled, fully complementary, and have relatively high damping factors.

Of course, there's a lot more to a great sounding amplifier than tight bass

Jan 25, 2017 15:31:58 GMT -5 Casey Leedom said:

So I've heard that one should looks for Power, Damping Factor and Slew Rate in order to grossly characterize one amplifier or another as having the fundamental basic characteristics for "tight, well-controlled bass". I've also heard commentary on "Push-Pull" amplifiers, being able to stop a woofer's motion, etc. with regard to this. And I'm sure there are tons of other basic amplifier parameters, various feedback schemes, etc. which add up to an amplifier being able to deliver "tight bass". But I've never found a "definitive" description.

Anyone want to take a pass at this? Just curious.

Casey

[Casey Leedom]

Thanks KeithL! I knew there'd be more to "tight bass" than any one single issue, but Damping Factor is good to know about. And of course, more to Good Sound than simply "tight bass"!

Part of my motivation in asking are my new Legacy Audio Focus SE Left/Right and Marquis HD Center. All of them have 2 12" Woofers! They are relatively high sensitivity at ~95db so the 200Watts/Channel/8Ω of my MPS-1 have been more than enough to make things "loud". The Focus SEs go down to 18Hz and the Marquis HD to 22Hz. That strikes me as a lot of air to move and thus power to move it. So I've wondered what kind of demand that's been placing on the MPS-1 EPM-300 Amplifier Modules.

All of this is probably just rationalization for me buying your new XPA Gen3 Double-Wide 3 Channel Amplifier when it becomes available ... :-)

Casey

[garbulky]

Jan 25, 2017 18:41:54 GMT -5 Casey Leedom said:

Thanks KeithL! I knew there'd be more to "tight bass" than any one single issue, but Damping Factor is good to know about. And of course, more to Good Sound than simply "tight bass"!

Part of my motivation in asking are my new Legacy Audio Focus SE Left/Right and Marquis HD Center. All of them have 2 12" Woofers! They are relatively high sensitivity at ~95db so the 200Watts/Channel/8Ω of my MPS-1 have been more than enough to make things "loud". The Focus SEs go down to 18Hz and the Marquis HD to 22Hz. That strikes me as a lot of air to move and thus power to move it. So I've wondered what kind of demand that's been placing on the MPS-1 EPM-300 Amplifier Modules.

All of this is probably just rationalization for me buying your new XPA Gen3 Double-Wide 3 Channel Amplifier when it becomes available ... :-)

Casey

Those speakers deserve some high quality amplification. Don't mess around now! Don't compromise. Go for the best you can.

[stiehl11]

Jan 25, 2017 21:41:04 GMT -5 garbulky said:

Jan 25, 2017 18:41:54 GMT -5 Casey Leedom said:

Thanks KeithL! I knew there'd be more to "tight bass" than any one single issue, but Damping Factor is good to know about. And of course, more to Good Sound than simply "tight bass"!

Part of my motivation in asking are my new Legacy Audio Focus SE Left/Right and Marquis HD Center. All of them have 2 12" Woofers! They are relatively high sensitivity at ~95db so the 200Watts/Channel/8Ω of my MPS-1 have been more than enough to make things "loud". The Focus SEs go down to 18Hz and the Marquis HD to 22Hz. That strikes me as a lot of air to move and thus power to move it. So I've wondered what kind of demand that's been placing on the MPS-1 EPM-300 Amplifier Modules.

All of this is probably just rationalization for me buying your new XPA Gen3 Double-Wide 3 Channel Amplifier when it becomes available ... :-)

Casey

Those speakers deserve some high quality amplification. Don't mess around now! Don't compromise. Go for the best you can.

Here you go, gar CLICK ME. He's got a pretty sick amp already. As the saying goes; check yourself...

[garbulky]

Jan 25, 2017 22:23:35 GMT -5 stiehl11 said:

Jan 25, 2017 21:41:04 GMT -5 garbulky said:

Those speakers deserve some high quality amplification. Don't mess around now! Don't compromise. Go for the best you can.

Here you go, gar CLICK ME. He's got a pretty sick amp already. As the saying goes; check yourself...

But I thought he's looking to replace it? Maybe I read it wrong. All I'm saying is don't compromise!

[Casey Leedom]

Oh I'm not dedicated to replacing my MPS-1 — it's a fabulous amplifier. Worst case scenario, I'd keep that for all the other channels, etc. and just get something for the Legacies. But I started this thread to see if there's actually any sense in doing even that. The MPS-1 is obviously great, but are the EPM-300 Amplifier Modules going to have any problems with the 2x12" woofers in each speaker?

Casey

[creimes]

Bass traps, there I said it and no it's not one of those amps you buy at the local hardware store that claims 10,000 watts per channel, just some good old traps to trap ya know...the bass

Chad

[Casey Leedom]

"Bass Traps". Hhmmm, you get those at your local Fishing Supply? Those stores a fairly rare here in Palo Alto ... :-)

Casey

[hemster]

Bass traps below may or may not help your sound quality. 

[garbulky]

Even though bass traps don't quite capture the bass the way the name portrays, room treatments are quite beneficial in helping to tighten up the sound. I reccomend them highly, even if you do one, behind you on the wall at head level you can get a noticeable difference.
Your Legacys deserve room treatments if you haven't already!

[Casey Leedom]

Yes, more seriously, right after I got my new Legacies last May, I did look at room treatments — especially on the wall behind my listening position. I and a friend used a huge camping pad placed up there to see if we could hear any differences but nothing jumped out. I was focusing on the high frequencies to see if any track was harsh with hard reflections or overly damped, etc. I hadn't thought to listen carefully to the bass. I think the reason my friend and I couldn't hear any differences — aside possibly from not knowing what to listen for — is that the room is already fairly damped. But maybe we'll give it another listen.

Casey

[garbulky]

Jan 26, 2017 11:01:47 GMT -5 Casey Leedom said:

Yes, more seriously, right after I got my new Legacies last May, I did look at room treatments — especially on the wall behind my listening position. I and a friend used a huge camping pad placed up there to see if we could hear any differences but nothing jumped out. I was focusing on the high frequencies to see if any track was harsh with hard reflections or overly damped, etc. I hadn't thought to listen carefully to the bass. I think the reason my friend and I couldn't hear any differences — aside possibly from not knowing what to listen for — is that the room is already fairly damped. But maybe we'll give it another listen.

Casey

At that point, you may want to try actual room treatments, and possibly a bit more of it because you didn't really notice a difference. It's rare that you find a room that won't benefit from it. But some benefit more from others.

[brutiarti]

In my case, the most dramatic changes came from treating the left and right walls. After that, the corner traps tightening up the bass and i got rid of a boomy low frequency coming from the speakers. Adding subs later on, helped getting a more uniform and tight bass.

[siggie]

The main drawback to bass traps is that, if you don't clean them every week, your room starts to smell like dead fish.

siggie

[Casey Leedom]

In my room all of the corners are already fairly occluded with various furniture, etc. so there's certainly nothing really to do on the floor. It's possible that the upper corners could be treated, but event then, there's only one "real" corner in the line of speaker fire and that's already broken up so it's not going to work well as a corner reflector. In any case, I'll try experimenting again with my friend and see what we can find.

In the mean time, I look forward to the release of the new XPA Gen3 Double-Wide fully differential Amplifier Modules, and subsequent reviews from places like Audioholics, etc. I think that those may well end up being Emotiva's answer to having a Reference Amplifier to pair with the upcoming RMC-1 and XMC-2 ...

Casey

[pknaz]

Pretty much anything below about 300hz or so is almost entirely dictated by the room. Reach out to GIK Accoustics, they offer a free room analysis with no obligation to buy their products.