Emotiva XMC-2 Enhanced Bass

[BigDan79]

Hello,

I just got a new Emotiva XMC-2 processor and upgraded my Emotiva A-5175 to an XPA6. I wanted to get some more info on the enhanced bass settings. Is it common to enable this setting? Should I leave it off? I am running a 9.3.6 with this processor.

 

[Todd Anderson]

You could theoretically turn it on and set your mains to large... that way LFE is routed to both your mains and your subs. Personally, I'd only do that if you feel like your room is having issues with an even low-end response. Otherwise, I'd leave one configuration for movies with speakers set to small and LFE crossed over to the subs... and then a separate 2-channel configuration that has your mains set to large and no subs.

Of course, you can always try listening to your system with Enhanced Bass on with your front mains or your front three channels set to Large... see how you like it.

 

[BigDan79]

Thanks for the response. I will probably leave it off since I have 3 subs. It does seem like I need more bass for music. Would the best way to fix this be to have two presets for Dirac? One for movies and one for music.

 

[Todd Anderson]

I was just reading through the manual... it says to leave it disengaged for the best music playback experience.

If you feel like bass is lacking, I'd goose your target curve in the bass region and apply it to a preset that you use for music.

 

[Sonnie Parker]

I would never use it... and I really don't see why they include it as a feature... wasted processing really. I don't believe there is a way to measure and blend the LFE summed with mains and subs for a smooth response anyway.

 

[BigDan79]

Does it matter if you set your speakers to large or small?

 

[Todd Anderson]

That setting tells the processor to crossover LFE to the sub.

 

[Sonnie Parker]

I would definitely let your subs handle the sub 80Hz duties in the room.

 

[Travis Ballstadt]

That setting tells the processor to crossover LFE to the sub.

This is where people get confused, there is LFE, and there are low frequencies. LFE is a separate channel encoded into a surround mix - the .1 channel. Low frequencies are the low frequencies from the bed 7.x.x channels - the bed channels.

If I remember correctly, Emo’s “Enhanced Bass” also spreads the LFE channel across any main speakers set to Large.

Normally LFE (the .1) is sub only. Low frequencies from the bed channels go to main speakers set to Large, or are crossed over to the sub for speakers set to Small.

Or I could be wrong.

 

[Sonnie Parker]

That sounds correct to me.

Some processors no longer have LFE channels... but instead simply follow the crossover.

 

[BigDan79]

What is the difference between the large and the small setting for a speaker if the crossover is set to 80hz? Only to allow extended bass? I want to understand what the processor is doing for both large and small speaker settings at the 80hz crossover setting.

 

[Sonnie Parker]

When you set the speakers to small you will have a crossover available to route the bass of that speaker to the sub(s).

 

[Marc Lombardi]

I think I can clear up some confusion here. Please bear with me as I will get to Enhanced Bass and how it relates ....

1- when you have subs set to Mono or Dual Mono, bass management and LFE go to the subs. If you use center sub=LFE, then ONLY LFE goes to center sub and ONLY bass management goes to the other sub(s). If center sub=LFE and there are no other subs and any speakers (fronts typically) are set to large, then ONLY LFE goes to center sub and ONLY bass management goes to the large speakers.
2- you can only use Enhanced Bass if at least one set of speakers is large (fronts typically). It will run the large speakers full range AND send large speaker bass to the subs ... below the configured crossover frequency for the large speaker. You set that crossover by temporarily setting the speaker to small, set the crossover, set it back to large, and enable Enhanced Bass. In this case, if you have center sub = LFE and no other subs, bass management will go to the large speakers down to the crossover and then to the subs ... LFE still goes only to the center sub.
3- enabling Enhanced Bass does NOT send LFE to the large speakers as was the case with XMC-1. This is a good thing!

Please ignore what they say about Enhanced Bass not being good for music. The appropriate way to get a benefit from this feature is to set the crossover to the lower response limit of your large speakers. For example, my Magnepan 3.7's respond down to 40Hz, so I can set them to large and set the crossover to 40Hz. If anything happens below 40Hz it will go to the subs.

So ... if I set center sub=LFE, and fronts to large, and Enhanced Bass with crossover 40Hz ... all the small speakers get 3.7 Maggie bass down to 40Hz and then cross to the subs. This sounds GREAT with music! It also sounds great with movies. It's much better to let LFE go to the subs (and it will play up to the LFE limit of 120Hz before rolling off), and only use the subs for bass management below the range of your large speakers.

Note that the way Dirac Live works it does not measure large or small speakers with the subs simultaneously. If you use Enhanced Bass you should separately measure the response after Dirac calibration to see that the transition from large speakers to subs is smooth.

 

[Sonnie Parker]

The Emotiva may be different... I have not ready the manual, but the last processor I had that had Enhanced Bass simply took the LFE and routed it to the main speakers, so it made zero difference on stereo music. The only time it would come into play with music is if the music you were listening to had LFE encoded into it.

 

[Marc Lombardi]

Yes Emotiva is different and the XMC-2/RMC work differently from the XMC-1.

Enhanced Bass takes whatever signal is going to large speakers (in mono) and routes it to the subs below the configured crossover. In the XMC-1 that crossover was fixed at 80Hz which was not useful, and the XMC-1 also routed LFE back to the large speakers. In the new processors you can configure the crossover from 40Hz up in 10Hz increments. You still have the large speakers run full range and add the subs below the crossover.

Enhanced Bass in the new Emotiva processors does not add LFE to the large speakers. This is good because with the XMC-1 it did add back LFE and with some movies the diaphragms of the 3.7's slapped the magnets ... scary!

The only way LFE ever goes to the large speakers is if you have no subs configured. Then yes, LFE and bass management go to the large speakers and Enhanced Bass is not an option.

 

[Sonnie Parker]

Makes sense... and I've seen some "Enhanced Stereo" settings in some previous units... don't remember which, as I never used it. I just prefer good ole "Stereo" ... lol.

 

[BigDan79]

I think I can clear up some confusion here. Please bear with me as I will get to Enhanced Bass and how it relates ....

1- when you have subs set to Mono or Dual Mono, bass management and LFE go to the subs. If you use center sub=LFE, then ONLY LFE goes to center sub and ONLY bass management goes to the other sub(s). If center sub=LFE and there are no other subs and any speakers (fronts typically) are set to large, then ONLY LFE goes to center sub and ONLY bass management goes to the large speakers.
2- you can only use Enhanced Bass if at least one set of speakers is large (fronts typically). It will run the large speakers full range AND send large speaker bass to the subs ... below the configured crossover frequency for the large speaker. You set that crossover by temporarily setting the speaker to small, set the crossover, set it back to large, and enable Enhanced Bass. In this case, if you have center sub = LFE and no other subs, bass management will go to the large speakers down to the crossover and then to the subs ... LFE still goes only to the center sub.
3- enabling Enhanced Bass does NOT send LFE to the large speakers as was the case with XMC-1. This is a good thing!

Please ignore what they say about Enhanced Bass not being good for music. The appropriate way to get a benefit from this feature is to set the crossover to the lower response limit of your large speakers. For example, my Magnepan 3.7's respond down to 40Hz, so I can set them to large and set the crossover to 40Hz. If anything happens below 40Hz it will go to the subs.

So ... if I set center sub=LFE, and fronts to large, and Enhanced Bass with crossover 40Hz ... all the small speakers get 3.7 Maggie bass down to 40Hz and then cross to the subs. This sounds GREAT with music! It also sounds great with movies. It's much better to let LFE go to the subs (and it will play up to the LFE limit of 120Hz before rolling off), and only use the subs for bass management below the range of your large speakers.

Note that the way Dirac Live works it does not measure large or small speakers with the subs simultaneously. If you use Enhanced Bass you should separately measure the response after Dirac calibration to see that the transition from large speakers to subs is smooth.

Thanks for this reply. I understand it much better now. I will see what it sounds like both ways and see what happens. I just ran the Dirac room correction and it sounds amazing but it killed my bass. I am using the Harman +8 curve with +4 for the sub settings to get my bass back. I think I will have to run Dirac again when I have a spare hour without kids making noise.

 

[Marc Lombardi]

Thanks for this reply. I understand it much better now. I will see what it sounds like both ways and see what happens. I just ran the Dirac room correction and it sounds amazing but it killed my bass. I am using the Harman +8 curve with +4 for the sub settings to get my bass back. I think I will have to run Dirac again when I have a spare hour without kids making noise.

Very common to hear "Dirac killed my bass". You have to understand, one of the most important things Dirac does is eliminate the huge resonances that typically happen below 100Hz. The result is these peaks which can be as much as 10-15db between 40-60Hz are flattened out and this also has an effect in the time domain resulting in less "boom" to the bass also. This is accurate bass but it won't be what you're used to. That said ... if you want more then just use the curves or increase the level of your sub. If you post a screen shot of your Dirac measurements I may be able to comment further.

 

[BigDan79]

Very common to hear "Dirac killed my bass". You have to understand, one of the most important things Dirac does is eliminate the huge resonances that typically happen below 100Hz. The result is these peaks which can be as much as 10-15db between 40-60Hz are flattened out and this also has an effect in the time domain resulting in less "boom" to the bass also. This is accurate bass but it won't be what you're used to. That said ... if you want more then just use the curves or increase the level of your sub. If you post a screen shot of your Dirac measurements I may be able to comment further.

Here is the sub channel. Do you need other channels also?

 

[Marc Lombardi]

That's a good example. Look at that 18-20db peak at 25Hz! That's a room resonance that Dirac will pull down. If your L/R speakers respond that low they will also have the same peak, and flattening it out will be perceived as "less bass" at first but you may get used to it as accurate tight bass. Not much music content that low, but some movie effects like thunder and explosions can be. Notice also your sub is down about 5db between 40-100Hz. Dirac will lift that area.

This shows response up to 300Hz which is quite high for a sub. The LFE channel (the .1 in 5.1 or 7.1) only goes up to 120Hz. That's the Dolby spec for LFE content. Are all your speakers set to small? What crossovers are you using? Likely you're crossing them at 80Hz ... possibly lower for your L/R, and possibly higher for surrounds or center. No need to have Dirac correct up to 300Hz, so you should probably pull the curtain down to like 150Hz.

Here are my measurements for 7.1.4, with target curves (flat!) and predicted response.

 

[BigDan79]

I have all the speakers set to small but the left and right fronts and front wides.

 

[Marc Lombardi]

I have all the speakers set to small but the left and right fronts and front wides.

Dirac measurements give you information to help set your crossovers. Take a look at where each pair of speakers naturally rolls off and you can optimize your crossover points to only use the sub for the lowest frequencies that the speakers can't reach. You can also separate your Top speakers into separate groups of pairs if they could benefit from different target curves.

If your fronts go down to at least 40Hz they would benefit from Enhanced Bass with the crossover set to 40Hz.

 

[BigDan79]

So another question about extended bass. Does the bass management go to both the sub and the large speakers? If not I would be concerned that the main speakers would not be as good as the subs at creating bass.

 

[Marc Lombardi]

So another question about extended bass. Does the bass management go to both the sub and the large speakers? If not I would be concerned that the main speakers would not be as good as the subs at creating bass.

So defining some terms: LFE is the .1 in multichannel surround content like movies and it only goes to the sub, crossover settings do not affect LFE, and the Enhanced Bass settings do not affect the sub itself for LFE. Bass Management refers to sending the bass from small speakers to the sub, and this is done by setting the individual crossover frequency for each pair of small speakers based on their low frequency cutoff. The slope setting (12 or 24) affects Bass Management for all small speakers.

With your fronts set to large, if you enable Bass Management it will still run the fronts full range, but it will add the front speakers' content to the subs below the configured crossover point. The main speakers are probably better at producing bass within their range than the subs. So you have a choice depending on how low the mains go. If they go down to 20Hz you have no need for Enhanced Bass. If they go down to 40Hz then Enhanced Bass with crossover set to 40Hz would work ... or you may just want to set the mains to small and cross them at 40Hz.

Last thing I'll mention is that measuring the response separately from Dirac will tell you more about what's going on. Using Room EQ Wizard you can try different combinations and fine tune the crossover settings. Since Dirac runs without Bass Management or Enhanced Bass enabled, you can't see what's going on looking at Dirac measurements. I always measure the result with REW and sometimes tweak the Dirac curves to optimize the response.

 

[BigDan79]

OK. I think I understand it now. I bumped up the sub in Dirac as you mentioned and had a quick listen. The bass seems stronger, closer to what I had before. I need to listen to all of the normal go to scenes to see where it is. I agree, I need to run REW to see the room response. But I will say the XMC-2 sounds great. I was really surprised after running Dirac by the little things I hear now. Thanks again for your help!