REW

Conrad.

Moderator
I'm not sure I agree. I think it looks ok, although the integration could do with some work. This is a single, small-ish sub in a good sized room, it's never going to be ruler flat to 10Hz.

You're showing no signs of compression in those sweeps, but the crossover region could do with some work.

Can you measure the sub and speakers alone with a timing reference?

Measure sub on the LFE channel
Disconnect a main and measure the sub on main channel (this includes the crossover)
Measure the L, C, and R, with no sub

Do all of that with a consistent timing reference. The timing reference can be any speaker other than the sub, and not the speaker you disconnect for measurement 1. I use surround back left.

With these measurements we can play with the timing and see if we can improve over Audyssey's integration.
 

DodgeTheViper

Moderator
@blacksheep99

I don't agree either, it doesn't look too bad at all. And I wouldn't worry about only doing three Audyssey measurements. Just follow what Conrad is suggesting :smashin:
 

blacksheep99

Well-known Member
I'm not sure I agree. I think it looks ok, although the integration could do with some work. This is a single, small-ish sub in a good sized room, it's never going to be ruler flat to 10Hz.

You're showing no signs of compression in those sweeps, but the crossover region could do with some work.

Can you measure the sub and speakers alone with a timing reference?

Measure sub on the LFE channel
Disconnect a main and measure the sub on main channel (this includes the crossover)
Measure the L, C, and R, with no sub

Do all of that with a consistent timing reference. The timing reference can be any speaker other than the sub, and not the speaker you disconnect for measurement 1. I use surround back left.

With these measurements we can play with the timing and see if we can improve over Audyssey's integration.

Thanks Conrad. Integration? Those are just sub sweeps unless I don't understand (highly likely!).

Thats actually 2 subs. The Mono 12" and my XTZ 1X12

I'll try and measure a timing reference as you suggest. I may need to do some further reading as this aspect is all new to me. Appreciate the help.
 

blacksheep99

Well-known Member
One thing I did find a struggle with was getting the subs to the right level in the Audyssey app. Actually I ran it with them both showing outside the green zone on the hot side.
 

Conrad.

Moderator
What channel did you take the measurements on? I'm assuming they're full range measurements as there no sign of a crossover kicking at the upper frequencies. It could be LFE, but it's hard to see as it cuts off at 125Hz.

When you sweep, for subs go to at least 300Hz, or even 500Hz. When doing full range always go to 20,000Hz. It's free to measure and there'll always be a time when you wish you had the measurement and didn't. Better to have it and not need it than to need it and not have it.

If it's two subs, then the measurements we need are:

- each sub individually on LFE
- each sub on a main channel will the mains disconnected/inactive.
- optionally do each main separately with no subs

For each measurement turn Audyssey off.

Start there. We can then see what kind of response we can get with the subs in alignment.
I find I get the best results by aligning multiple subs and then presenting them to the processor as a single sub, letting it perform its auto EQ and then tweaking after that.

The timing reference is a pair of controls on the measure window. In the right column there's a dropdown marked timing. Change that Acoustic timing reference and that'll enable another control lower down marked Ref output. Choose a speaker in that control and when you measure you'll hear a high pitched timing signal from that speaker. That allows REW to compare all the measurements and removes any differences due to processing, lag, etc.

1604143270191.png

Do you have a minidsp?
 

blacksheep99

Well-known Member
Thanks. I'll try find some time later today to attempt this. I did run some full sweeps on the other speakers but the graphs I put up were the LFE running from 16hz to 200hz.

No Mini-DSP as yet.
 

blacksheep99

Well-known Member
So my 2nd Mono 12" turned up today. I haven't had the time to do as Conrad suggests above. Think that is one for the weekend. I did however run a few LFE sweeps after a quick (3 pos) Eq. I also ran sweeps on the main speakers.

Within Audyssey the subs were in the green after I turned the gain down. I checked the SPL from the FL speaker and set the AVR to output 75db prior to the sweeps. What I don't understand is why the subs are outputting so much more, is that room gain?

All channels (no height).
Full sweeps mono sub and centre3.jpg


LFE (Subs in opposing corners, FL and RR). Monolith 12" both ports open
LFE sweeps Mono x2.jpg


I'm just playing and learning right now but it's interesting. I would like to try both subs behind the MLP but worried about how that may end up sounding. Aesthetically it would be better in the room.
 

Conrad.

Moderator
If you’re measuring on the LFE channel then that’s boosted by 10dB relative to the other channels. That’s usual.
 
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Bilbo 69

Active Member
Advice needed please
What type of lead should I be using from the laptop to the AV receiver
HDMI or USB ???
 

blacksheep99

Well-known Member
Not sure if this is the best place to ask but it's certainly relevant. If I want to get a minidsp for 2 subs is it the 2x4HD I need or would the 2x4 suffice? From what I read it seems the 2X4HD is the way to go?
 

Bilbo 69

Active Member
Read a fair bit my self and going by all the YouTube videos the 2x4 HD one is the one to go for a bit more expensive but well worth it as it does a lot more apparently
 

Lesmor

Distinguished Member
Not sure if this is the best place to ask but it's certainly relevant. If I want to get a minidsp for 2 subs is it the 2x4HD I need or would the 2x4 suffice? From what I read it seems the 2X4HD is the way to go?
if you feel that you need one get the 2 x 4 HD
 

Lesmor

Distinguished Member
Thanks. I don't just yet but I'm currently going down the rabbit hole of dual subs and REW :D
Well you don't need it for REW
depending on how good a job your AVR does on EQing subs (Duals should be EQd as one) you might not need it ?
If you intend using BEQ then you definitely need it
 

blacksheep99

Well-known Member
Well you don't need it for REW
depending on how good a job your AVR does on EQing subs (Duals should be EQd as one) you might not need it ?
If you intend using BEQ then you definitely need it

That's where I am currently. I'm using REW with my UMIK-1 to check the response of my two subs in different positions. Hopefully I can get a decent result with it and my x4500h.
 

Lesmor

Distinguished Member
That's where I am currently. I'm using REW with my UMIK-1 to check the response of my two subs in different positions. Hopefully I can get a decent result with it and my x4500h.
Your Denon should be able to do a good job of the dual subwoofer EQ (double check with REW) so unless you want to go down the BEQ rabbit hole at this time you don't really need a miniDSP
you probably know this already but it is how the combine response looks prior to EQ that is important
 

cheyneb25

Novice Member
Hello all! First time poster here on this site, but I have frequented the AVS and Audioholics sites as well. Over the last 8 months or so I have dipped my toe into the water with using REW and I've been trying to get comfortable using it with my Minidsp 2x4 HD for bass management in my non-dedicated home theater. I have 6 Bic F12 subs spread throughout the room to try and mediate the room modes because it is an oddly shaped room.
I've been able to improve the response after my 1st run of attempts to time-align them w/ delay and inversion but there is still plenty left to be done. I have a Dropbox page (links posted below) with some .mdat files and I was hoping to get people's thoughts on what they think of the frequency response since I'm still not very knowledgeable on what it all may or may not indicate.





I also included some additional attachments below (room pics and REW screencaps) for a little more context. I currently use a hybrid methodology of multi-sub techniques roughly based on info from the work done by Geddes, Toole, and Welti, but I'm very open to any suggestions/tips people may have about the placement, etc..
In the .mdat files on my Dropbox page, the 'first configuration' is what I've been using for the last few months now, and I recently did another attempt labelled as the 'new configuration'. I did add a little smoothing to the full frequency sweep just to make it a lil more readable, just FYI. I recently upgraded my bed layer speakers to GoldenEar but I have not yet tried to implement any EQ on the Bic subs or on the speakers, I'm waiting until after I get everything else fully tweaked to do anything like that.
I turned off the Dynamic EQ in my SR7009 Marantz amp when I was running my REW sweeps but for whatever reason it still looks like the bass is getting a bit of a bump compared to the higher frequencies, not totally sure why. And apologies if the files I posted below here are not up to par, I'm still fairly new to doing it.
Looking forward to hearing everybody's input, thanks in advance!
 

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Conrad.

Moderator
Hey @cheyneb25, I keep seeing the email notification about this post (which I kept) and thinking I must respond.

Sorry it's been so long, I'll have some time tomorrow and as nobody else has I'll have a look your measurements and reply.
 

cheyneb25

Novice Member
Hey @cheyneb25, I keep seeing the email notification about this post (which I kept) and thinking I must respond.

Sorry it's been so long, I'll have some time tomorrow and as nobody else has I'll have a look your measurements and reply.

No worries man. There are always other aspects of my theater setup for me to ruminate on while I wait for the smarter people around here to lay some wisdom on me, lol. I'm just looking forward to getting other people's perspectives on what I've done with everything so far because I feel like I probably overlooked something.
 

Conrad.

Moderator
Hey. I had a very quick look, there's not a lot to work with having just single full range sweeps. It looks like your subs are something like 20-30dB hot which is insane. Even for me.

Some questions:

- How are you level matching your subs? Are you setting them all to 75dB each along with your speakers?

- Are you running Audyssey?

- How have you configured your minidsp with six subs?

Can you take the following measurements, with Audyssey off, all timing and EQ reset in the minidsp and the AVR:
- each sub, individually, on the LFE channel (4), with a timing reference

In fact, let's just start there. With that we can look at the time alignment to get the smoothest response.

You have a set-up like me with a pair of VNF subs. This changes things.

Usually the practice is to time align all the subs in the room, then apply the same EQ to the combined response (so the same EQ on all subs). This can lead to a lumpy response on individual subs, but the combined response at the MLP is smooth, which is usually all that matters.

That doesn't work for VNF subs though. It's no good having big humps and dips on the subs right behind the couch as it gives a weird feeling.

I'd be tempted to look at the four far field subs individually, time align them, then level match them and integrate them with the mains. Then I'd look at the two VNF subs as a separate sub, time align them and EQ them hard, ruler flat, and lower the gain. That'll give you all the TR in the back of the couch without disrupting the rest of the room. We can time align the VNF subs with the other four so that they don't ruin the response.

We can see whether that approach works once I can see the individual measurements.
 

cheyneb25

Novice Member
Hey. I had a very quick look, there's not a lot to work with having just single full range sweeps. It looks like your subs are something like 20-30dB hot which is insane. Even for me.

Some questions:

- How are you level matching your subs? Are you setting them all to 75dB each along with your speakers?

- Are you running Audyssey?

- How have you configured your minidsp with six subs?

Can you take the following measurements, with Audyssey off, all timing and EQ reset in the minidsp and the AVR:
- each sub, individually, on the LFE channel (4), with a timing reference

In fact, let's just start there. With that we can look at the time alignment to get the smoothest response.

You have a set-up like me with a pair of VNF subs. This changes things.

Usually the practice is to time align all the subs in the room, then apply the same EQ to the combined response (so the same EQ on all subs). This can lead to a lumpy response on individual subs, but the combined response at the MLP is smooth, which is usually all that matters.

That doesn't work for VNF subs though. It's no good having big humps and dips on the subs right behind the couch as it gives a weird feeling.

I'd be tempted to look at the four far field subs individually, time align them, then level match them and integrate them with the mains. Then I'd look at the two VNF subs as a separate sub, time align them and EQ them hard, ruler flat, and lower the gain. That'll give you all the TR in the back of the couch without disrupting the rest of the room. We can time align the VNF subs with the other four so that they don't ruin the response.

We can see whether that approach works once I can see the individual measurements.



Hey Conrad, thanks for responding here. I tried not to be long-winded but I do have some answers to your Q's:

1. - There was a video tutorial posted on an AVS thread that I used to help me with setting up everything. The video is from a YouTube channel called HomeTheaterGurus, I used his instructions on episodes 7 and 8 to level match and align my subs. Since all of my subs are identical I have the volume for them all turned up to the same point, the 10:15 position if it were a clock (or at a 3 on a 0-10 scale). And yes, I do have them set around 75dB when I run Audyssey. That being said, after I run Audyssey I implement what I believe is called a 'gain hack', which is to turn everything down in the AVR (trim, level, and sub adjustment) for the sub channel and then turn up the volume on the subs themselves to get it all back to where it should be. If the hack is legit and to be believed, then it's supposed to optimize the dynamics and punchiness of the bass and make the most of them.

2. - Yes, I do run Audyssey. After I have the subs aligned in the minidsp I run Audyssey using all the positions that it allows, and It usually ends up setting the 'virtual' sub distance in the AVR for around 25'. My plan is to upgrade my AVR sometime in the next few months so that I will have more flexibility to make more adjustments to what any room correction software would want to do for the higher frequencies. My Marantz SR7009 has been a great AVR but I don't have even the Audyssey Editor app that is offered for some of the Denon/Marantz AVRs to give myself more options (like setting a cutoff frequency in Audyssey so that it wont apply any EQ past a certain point).

3. - Configuring 6 subs with a minidsp HD 2x4 was a little challenging since it only has 4 outs, but what I did was use a Y-splitter for the 2 subs in the front corners and also for the 2 subs behind the couch, the other 2 subs are done individually. When I aligned them all, I started with the one furthest away, then the 2 VNF subs next, then the front corner subs and lastly the one elevated midway up the wall behind the TV. It's not 100% ideal, and at some point I would like to get a minidsp unit that can handle all 6 subs individually. I had considered upgrading to a minidsp 2x8 or 4x10 so I would have enough outs to do each sub individually, but, as with everything, there are pros and cons to getting a different minidsp unit. If you want the exact settings that I have set up in the minidsp for all of the subs (delay and inversion) just let me know.

4. - I will definitely get you the measurements you want for all of the subs individually with Audyssey off and the minidsp reset, and once I do I'll post the DropBox links for them here on this thread for your review. One question though, I'm not totally certain what you mean when you say for me to do it 'with a timing reference'; I may just be misunderstanding something obvious though, so judge me gently, lol.

With your questions having been addressed, I have some additional commentary as well. When it comes to the 2 VNF subs, they are less than 2.5' apart (close enough to be classified as co-located?) and are hooked up to the minidsp on just one output (using a Y-splitter to accomplish that). So, from my limited understanding I believe they act as 1 sub when I am doing the alignment process. The room is about about 25' going from front to back, and the 2 subs that are behind the couch are about 11' from the front of the room, so very close to being in the null that's supposed to be in the middle of a given room. In addition to giving some nice TR for the people on the couch, I thought that it may also help to mitigate the null by locating them there and improve the perceived response.
Integrating my subs with my mains is one of the next big steps that I planned on taking but I haven't done so yet, I'm still in the 'baby steps' phase of my learning curve, lol. I will say that after I upgraded my base layer of speakers to the GoldenEar, I changed the crossover to 80Hz and they sound like they blend together better now.
Before I got the minidsp I had just been splitting the LFE signal coming from the 2 independent sub outs on the Marantz for the 4 subs that I was using at that time, and when I was doing it that way I did indeed have the gain turned down a lot more on the 2 VNF subs. Once I got the minidsp and added in 2 more subs I level matched all 6 of them; I liked the improvement and they didn't come across as too overwhelming.
As I said before though, I only know enough about all this stuff to get myself in trouble and there is still plenty of work to be done on getting everything as good as is possible. Optimizing my room has been a long process... Over the course of about 4 years I went from having 1 sub and no minidsp and very little understanding about the home theater hobby to where I am now, so it's been quite the journey, lol.
 

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