Incorporating MiniDSP With Audyssey XT32

[AcuDefTechGuy]

I guess what is safe for sub is not safe for SVS sub section. If you start using sub amp for SVS, SVS sub section becomes the weakest chain in the system.

He'll have to check with the SVS engineers/designers to see if they fully approve. I have no idea if their XO designs for the Bass + Mid/Treble are anything like RBH and NHT.

 

[AcuDefTechGuy]

Many experienced speaker engineers (Linkwitz, Revel, KEF, Dennis Murphy, etc.) believe you can easily achieve awesome BASS, Midrange, and Treble in a SINGLE speaker LOCATION.

So these experienced speaker engineers would disagree with the statement that somehow it is extremely difficult to achieve superb bass together with superb mid/treble if the mid/treble are in the same speaker location as the bass.

I easily get absolutely superb treble/midrange and chest-pounding-bigger-than-life-crazy bass at the same time with my towers (treble/mid in same location as bass).

But it may not be that easy for every case. Just like it may not be that easy for every person who uses bookshelf + subwoofers in different locations.

 

[Pogre]

I guess what is safe for sub is not safe for SVS sub section. If you start using sub amp for SVS, SVS sub section becomes the weakest chain in the system.

The sub section is pretty robust in the towers (two 8" woofers in each). Like ADTG said, I wouldn't want to use a 2000w amp for them. If I were to use a separate amp on the woofers I could bump the gain a little in the sub section of the towers.

This is a bad idea. What did SVS (or whichever brand) implement for the woof to mid passive crossover, a LR4 type presumably? Regardless, with passive crossovers, once you start giving one side more power than the other you'll inevitably shift crossover points and get less than flat summing at the 'new' crossover frequency.

I'm very cautious of messing something up. I would never attempt it without consulting SVS and doing a lot of homework first.

 

[ski2xblack]

That's why before doing anything, he would have to check with SVS engineering.

And they would probably say, 'sure, that will work', and if you press them on it, they would admit that using different amps that have different gain for the lp and hp passive filters would not produce the results that they carefully engineered. That's just physics.

Passive bi-amping is kind of silly IMO, particularly if you just want more bass. It seems like a hugely more complex and expensive method than just adjusting the tone controls or eq.

 

[ski2xblack]

I'm very cautious of messing something up. I would never attempt it without consulting SVS and doing a lot of homework first.

Well, you wouldn't mess things up in terms of speaker damage unless you misapplied too much power. But, with passive networks, they are designed assuming that the gain of the amp is consistent (amplified using one amp) for the lp and hp sections of the network. If you change the gain on one side or the other, you're fundamentally changing the crossover, altering how the two drivers blend together in terms of frequency and phase, which will change the crossover point and result in who knows what sort of overall summing between the drivers. This is passive networks 101 level stuff, and one of the reasons why passive bi-amping can result in sub-par outcomes.

 

[Pogre]

Well, you wouldn't mess things up unless you misapplied too much power. But, with passive networks, they are designed assuming that the gain of the amp is consistent (amplified using one amp) for the lp and hp sections of the network. If you change the gain on one side or the other, you're fundamentally changing the crossover, altering how the two drivers blend together in terms of frequency and phase, which will change the crossover point and result in who knows what sort of overall summing between the drivers. This is passive networks 101 level stuff, and one of the reasons why passive bi-amping can result in sub-par results.

That makes sense to me. It doesn't sound like something I want to do, but I might ask SVS just to see what they say.

 

[MrBoat]

Mr Boat
Are you trying to insinuate I'm a bassaholic or something?

Okay, okay. I like lots of bass. I can no longer deny it. There ain't no blappy bass in my house though!

No, not trying to insinuate that. Sorry if it sounded that way. More about bass with regard to measurements vs. music, and HT sound effects equipment vs music playback. The friend who auditioned his sub in my home was not from the same era as the music I sometimes listen to and he is seemingly more a measurementphile than an audiophile in that regard. He even adds rumble to acoustic guitar music.

When I try to explain to him what certain bass frequencies are supposed to sound/feel like, he doesn't get it unless it is something intense and that ends up being the cure for everything.

 

[Pogre]

No, not trying to insinuate that. Sorry if it sounded that way. More about bass with regard to measurements vs. music, and HT sound effects equipment vs music playback. The friend who auditioned his sub in my home was not from the same era as the music I sometimes listen to and he is seemingly more a measurementphile than an audiophile in that regard. He even adds rumble to acoustic guitar music.

When I try to explain to him what certain bass frequencies are supposed to sound/feel like, he doesn't get it unless it is something intense and that ends up being the cure for everything.

I know man, I'm just jerking your chain a little.

I appreciate your perspective on things. I might not always agree, but you have a way of thinking outside the box sometimes and I like it. You've given me food for thought more than once.

 

[ATLAudio]

@Pogre

What I did…

Ran initial sweep with Audyssey off, distances and levels set to default. I noticed a large hump at 60hz

1. Used REW/Mini DSP Room EQ Wizard to give relatively flat response. I actually used the REW Room EQ wizard and liked what it gave me. Failing to do this, or at least lowering the 60hz bump, prior to running Audyssey resulted in large steep roll off after 24hz, post Audyssey. I get the sense that this is why folks sometimes complain about low bass post-audyssey.
2. Ran Audyssey MultEQ XT32. This was done to achieve to flatten bass in front towers, set proper distances, and set reference volume matching.
3. Used REW/Mini DSP to adjust a few notch filters for final smoothing, and set low shelf boost to taste.

 

[PENG]

Oh you evil genius you! Removing the jumpers does separate, at least it did with my bookshelves. I haven't removed the jumpers on my towers yet. That sounds like a pretty cool solution, but I think I need to do a lot more homework before I go disconnecting passive crossovers and bypassing them.

Jumper disconnected = separate but not bypass, to bypass you have to access the XO inside obviously.

 

[Pogre]

@Pogre

What I did…

Ran initial sweep with Audyssey off, distances and levels set to default. I noticed a large hump at 60hz

1. Used REW/Mini DSP Room EQ Wizard to give relatively flat response. I actually used the REW Room EQ wizard and liked what it gave me. Failing to do this, or at least lowering the 60hz bump, prior to running Audyssey resulted in large steep roll off after 24hz, post Audyssey. I get the sense that this is why folks sometimes complain about low bass post-audyssey.
2. Ran Audyssey MultEQ XT32. This was done to achieve to flatten bass in front towers, set proper distances, and set reference volume matching.
3. Used REW/Mini DSP to adjust a few notch filters for final smoothing, and set low shelf boost to taste.

Thank you! I'm gonna have to do some more homework because I haven't used REW for anything aside from taking measurements. Looking at my charts, do you think it's worth the effort? It's not terrible right now and sounds quite good. I'm just ocd'ing.

 

[Pogre]

Jumper disconnected = separate but not bypass, to bypass you have to access the XO inside obviously.

Gotcha. At first I thought that's what he was suggesting. Like an active filter on the bass section. I understand now what he means.

 

[PENG]

@Pogre

What I did…

Ran initial sweep with Audyssey off, distances and levels set to default. I noticed a large hump at 60hz

1. Used REW/Mini DSP Room EQ Wizard to give relatively flat response. I actually used the REW Room EQ wizard and liked what it gave me. Failing to do this, or at least lowering the 60hz bump, prior to running Audyssey resulted in large steep roll off after 24hz, post Audyssey. I get the sense that this is why folks sometimes complain about low bass post-audyssey.
2. Ran Audyssey MultEQ XT32. This was done to achieve to flatten bass in front towers, set proper distances, and set reference volume matching.
3. Used REW/Mini DSP to adjust a few notch filters for final smoothing, and set low shelf boost to taste.

I really want to try it on my stereo system. Is it possible to use it to EQ the sub only? Sort of like Audyssey's L/R bypass.

 

[ATLAudio]

I really want to try it on my stereo system. Is it possible to use it to EQ the sub only? Sort of like Audyssey's L/R bypass.

Perhaps I don't follow... Are you asking if it's possible to EQ only the sub with REW/MiniDSP? If so, that's the only way I ever do it.

 

[2channel lover]

I have the mini so I might try and tackle it. If I were working right now I wouldn't have time for stuff like this, but I'm not so I have time on my hands. Honestly it keeps me busy and that's welcome. I'm not over here twitching, sweating and swearing at stuff. If it starts becoming un-fun I'll drop it. I think I have it pretty decent just the way it is and can stop and be very happy with my system.

Good...so the poking around was worth while.

I missed a few posts...how did you arrive at this point in bold? Direct? placement?

 

[AcuDefTechGuy]

Jumper disconnected = separate but not bypass, to bypass you have to access the XO inside obviously.

Right. The 2 passive internal XO would still be there.

But if they are set up so that the 2 XO are completely separated, then they will become 2 separate passive XO or 2 separate passive speakers?

And you can power 2 separate speakers with 2 separate amps and control the volume/level of each speaker.

 

[ski2xblack]

If the Bass XO is COMPLETED SEPARATED (no longer are connected) from the Treble/Mid XO, then they would become 2 COMPLETELY SEPARATE speakers, no ?

Now the Bass XO would still be there, but it is completely separated/disconnected from the other XO.

Yes, it's still there, unless you rip them completely out and go fully active. You cannot take some shortcut to active speakers by simply employing passive bi-amping, and that's what you are proposing by the suggestion of using a separate amp for the woofers and adjusting the gain, in lieu of tone controls/eq.

But the separate hp and lp filters still being there doesn't change the fact that it was designed on the assumtion that both sides were driven with the exact same gain from the amps. You change that, and you've changed the fundamental paramaters that the networks are dealing with.

Keep in mind that this is the basic approach of passive networks from a speaker design and engineering standpoint. The appearance of separate binding posts for high and low sections is more a reflection of marketing forces than anything else.

 

[AcuDefTechGuy]

Here is the S&V review of the NHT Classic Four tower.

https://www.soundandvision.com/content/nht-classic-four-surround-sound-speaker-system-page-2

They SIMPLY remove the JUMPERS, which disconnects the XO from each other. Of course, this does not remove or bypass any passive internal XO.

Then they SIMPLY used an external XO (which could be the AVR XO) + external amp to power the Bass.

So the AVR L/R speaker outputs would feed the top binding posts of the towers and the external subwoofer amp (with volume control like a separate subwoofer) would feed the bottom binding posts of the towers.

So in effect, the Classic Four becomes 2 separate speakers: bookshelf + subwoofer.

Again, I don't know if the SVS's internal XO are designed like the NHT and RBH.

 

[AcuDefTechGuy]

Yes, it's still there.

Yes, I know the passive XOs are still there. The passive internal Mid/Treble XO and the passive internal Bass XO are still there.

Unless you know something that RBH and NHT do not know, it is being done effectively. You can INCREASE and DECREASE the VOLUME of the woofers like you can with a separate subwoofer.

I don't know about all the different XO designs. But according to RBH and NHT and the S&V Magazine review of the Classic Four, you can still actively power the BASS section of the tower using EXTERNAL Crossover and Amp.

Read here:

https://www.soundandvision.com/content/nht-classic-four-surround-sound-speaker-system-page-2

Bottom line, the BASS section of the tower (with external XO and amp) becomes a separate subwoofer.

Again, I don't know of all the different XO designs to say if this is the case for all of them or just a FEW specific designs.

 

[Andrein]

Unless tower and sub are very close to each other (which might be a problem in itself) you would want to eq sub section and sub separately, right?

Yes, I know the passive XOs are still there. The passive internal Mid/Treble XO and the passive internal Bass XO are still there.

Unless you know something that RBH and NHT do not know, it is being done effectively. You can INCREASE and DECREASE the VOLUME of the woofers like you can with a separate subwoofer.

I don't know about all the different XO designs. But according to RBH and NHT and the S&V Magazine review of the Classic Four, you can still actively power the BASS section of the tower using EXTERNAL Crossover and Amp.

Read here:

https://www.soundandvision.com/content/nht-classic-four-surround-sound-speaker-system-page-2

Bottom line, the BASS section of the tower (with external XO and amp) becomes a separate subwoofer.

Again, I don't know of all the different XO designs to say if this is the case for all of them or just a FEW specific designs.