Would antimode help with two subs?

[indus]

Hi

At the moment I have a Monolith for sale and an Ultra. Before the former goes I was wondering what the two would sound like together.
My scientific knowledge of these matters is minimal. I do have an antimode and was wondering whether this could be used somehow to integrate the two?

Thanks

 

[Member 639844]

Well it has one input and two outputs, and can combine the results of 2 measuring positions (although thats probably not that much to do with it anyway) so it probably is usable, but I dont think it has to capability to manipulate 2 subs separately. Basically each sub would still be doing the same thing so results might not be spectacular, or any different from running a single sub.

TBH I would think you would need 2 antimodes to properly run 2 subs.

 

[binbag]

Try running one from each phase output with the sub phase settings matched to the output on the anti-mode. In all the stuff I read prior to getting mine I'm sure this was offered as an option with two subs.

 

[Member 639844]

Try running one from each phase output with the sub phase settings matched to the output on the anti-mode. In all the stuff I read prior to getting mine I'm sure this was offered as an option with two subs.

Ive read this too, but like I say I think it takes the reading of both subs and apply a single solution thats then reproduced by both subs. Fine if they are stacked but not entirely accurate if they are spread out, which is the best way to benefit from a twin sub setup.

Correct me if im wrong though.

 

[bazonix]

well i actually asked this question on the anti-mode thread a while ago... and had no response... but im not one for lying down and researched the question myself.... especially as i have more than 2 subs....

i would not use both phases as described above and as in the review posted by russ....

i had already emailed dspeaker and the reply i got:

First connect both subwoofers to the 8033 using the Y-cable. After this,
calibrate 8033 with both subwoofer on (and at about the same
gain-level). After the 8033 has calibrated, you can calibrate AVR again
to get the right volume and distance setting. This will lead to optimal
result using 8033 with multiple subs.


and actually using it practise, it really works..... i have no more localisation which was plaguing my set up... and the control i have over my bass is well, ridiculous!! all sweet now!!

nice one

 

[al_bert]

apply a single solution thats then reproduced by both subs. Fine if they are stacked but not entirely accurate if they are spread out

You're using the word "accurate" wrong here . Anti-mode will always "accurately" correct the response it sees. You mean "best possible achievable with two subs". Anti-mode will measure the combined room + sub response regardless of how many subs you have connected and where they are located (on the US side of the pond they've used 4 or even more) and flatten the peaks.

With more than one sub spread into the room you usually have a better starting point and are less likely to have a null and the final result will thus be better than with co-located subs.

What could theoretically be done with two independent sub outputs in an EQ is to affect the nulls also. Separate control could be used to move a bad null somewhere else in the room. At the same time you can cause another to appear, so it certainly isn't easy. You can also try this with Anti-mode by adjusting the sub phases so that you don't see a bad null at the listening position (REW or some other tool needed), then letting Anti-mode correct that system.

Using two anti-mode units do not give any advantage. They would just correct the subs independently and I suppose the corrections of the two averaged would quite closely follow the correction made by a single unit.

 

[Member 639844]

Excellent, and excellent news. Nice one Baz, this just took the antimode up a notch in my estimation which means its even more VFM .

Am I right in assuming that you keep the splitter in the setup after EQ to run both subs. I suppose you could look at it a different way to how I described before as being not entirely correct. I know of one member with a twin sub setup and the subs have auto EQ built in. He has to EQ them individually and each sub corrects its own response for room effects, but this doesnt take into account any additional effects caused while the other sub is running. Running the antimode like this obviously does account for the two (or more) subs running simultaneously. I wander which method is best.

I guess this is somewhere the AS-EQ1 would come into its own, in that it does what the antimode does but can correct the subs individually. Add to this its speakers inclusion into the EQ measuring and you can see why its 3 time the cost. I wander if the end result means its worth it though?

edit: cheers albert, that makes sense, and clarifies Baz's post and what its made me think.

 

[indus]

well i actually asked this question on the anti-mode thread a while ago... and had no response... but im not one for lying down and researched the question myself.... especially as i have more than 2 subs....

i would not use both phases as described above and as in the review posted by russ....

i had already emailed dspeaker and the reply i got:

First connect both subwoofers to the 8033 using the Y-cable. After this,
calibrate 8033 with both subwoofer on (and at about the same
gain-level). After the 8033 has calibrated, you can calibrate AVR again
to get the right volume and distance setting. This will lead to optimal
result using 8033 with multiple subs.


and actually using it practise, it really works..... i have no more localisation which was plaguing my set up... and the control i have over my bass is well, ridiculous!! all sweet now!!

nice one

Hi Bazonix.

I take it the Y cable is just a RCA splitter?

When you calibrate the AVR, how will it determind distance settings? I'm sure mine is only able to detect one sub, so how would that work?

Many thanks

 

[Member 639844]

Hi Bazonix.

I take it the Y cable is just a RCA splitter?

When you calibrate the AVR, how will it determind distance settings? I'm sure mine is only able to detect one sub, so how would that work?

Many thanks

I would assume that after the antimode calibration the two subs will act as one, so the AVR would detect a distance as set by the antimode what ever that would be. I guess that would be an average of the two distances to your listening position from each sub. For it to work correctly though you first amp auto setup (Audyssey) position that is normally your central listening position would have to be the same place you put the antimode mic when setting up the subs.

Feel free to correct me though anyone.

 

[bazonix]

hi again

i sometimes read into things too much, but its always better to be extra certain than so so...

in my particular case i emailed dspeaker, svs usa (jack, ur a star)and had help from fellow member suniil.... thanx a lot guys firstly

the rca cable im using is actually a y-splitter cable, i have a custom install (done myself) and there were so many wires coming from the hole through the wall i physically couldnt get another sub cable through... that was my biggest concern, but speakin to jack at svs put me straight....

basically i split the feed at the end of the sub cable, bought an in-line female to female connector, attached that to the splitter so i was able to then add the male side of the first cable into 2 equal length sub cables which each took a subwoofer...

the connections for me from the avr:

avr----cable-----anti-mode----cable----y-splitter----2 cables----2subs

iv totally discarded any auto set up and manually calibrate now.... so 2 subs should give approx 6db increase when both on, so setting the spl meter to 70 and calibrating the speakers to 75.....

then run antimode and then calibrate one sub at a time to approx 75db.... then test with both on... and i was getting my 6db increase yay!!

you actually increase the sub distance by 90cm but even if u dont, its not a major deal as the human auditory system would struggle to pick up differences... i tried both and couldnt tell but instead of 1.5m, iv set both subs to 2.4m anyway... again, another concern is phase when running two subs, but its been taken care of with the anti-mode in respect that both subs are set to '0' and work in tandem greatly..... im very happy with my set up now

nice one

 

[bazonix]

just to clear up the speaker distance.... you add the two distances if using 2 subs and divide by 2 to give average, then add 90cm.

 

[al_bert]

then run antimode and then calibrate one sub at a time to approx 75db.... then test with both on...

Changing the relative volumes of the subs will change the room response (unless the subs are strictly co-located).

To get the best result, first calibrate the subs (gain-match or level-match), then run Anti-mode calibration with both subs on at their intended volumes. Do not change the relative volumes of the subs after the Anti-mode calibration.

If the subs are the same make and model, I think it would make more sense to gain-match (volume at equal positions) them instead of level-matching them (equal sound pressure at listening position). This will provide you the most headroom and you can then change the sub level (compared to speakers) more easily from both the AVR and the sub end.

 

[indus]

Thanks guys. I'm going to see if I can get hold of a splitter today from Maplins and have a go.

Just to be clear, is there any reason I can't do this:

Sub cable from AVR to Antimode

Splitter inserted into output hole of antimode

One cable for each sub coming from the splitter

Thanks

 

[al_bert]

is there any reason I can't do this

No, it's fine. Go for it.

 

[bazonix]

To get the best result, first calibrate the subs (gain-match or level-match), then run Anti-mode calibration with both subs on at their intended volumes. Do not change the relative volumes of the subs after the Anti-mode calibration.

i thought this but it doesnt matter in fact, i emailed dspeaker with reference to this too and they told me as long as the anti-mode had calibrated the subs in tandem, its job is done. the user can then adjust the gains as required to achieve the right amount of bass

a problem for eg: if ur gains are at 11 o clock, the thump that will be generated by the anti-mode would bottom out most subs and id be very concerned if i was hearing this kind of noise.... the yellow slip in the box confirms that the gain should be reduced....

indus: do not think because u have 2 subs that they will work together.... you have a very difficult situation in that ur subs are not matched in the slightest. i would concerm myself with actually setting up the ultra first, as it should suffice better than 2 poorly set up subs any day, and i feel thats what u will end up with.

 

[Member 639844]

Thanks guys. I'm going to see if I can get hold of a splitter today from Maplins and have a go.

Just to be clear, is there any reason I can't do this:

Sub cable from AVR to Antimode

Splitter inserted into output hole of antimode

One cable for each sub coming from the splitter

Thanks

Do you intend to run the subs stacked/together or separated. If you dont separate them you'll get no benefits at all. Together you will get a bit of spl increase if the subs are equal, but as they arent and the Ultra will go louder anyway there isnt really any benefit to this. For your experiment to be of value you really need to try the subs in different positions. Of course you can try stacking them, dont take my word for it after all, but generally speaking you'll just get the same performance as the better of the 2 subs, or it will drop because of the lower performance one.

 

[Member 639844]

Changing the relative volumes of the subs will change the room response (unless the subs are strictly co-located).

To get the best result, first calibrate the subs (gain-match or level-match), then run Anti-mode calibration with both subs on at their intended volumes. Do not change the relative volumes of the subs after the Anti-mode calibration.

If the subs are the same make and model, I think it would make more sense to gain-match (volume at equal positions) them instead of level-matching them (equal sound pressure at listening position). This will provide you the most headroom and you can then change the sub level (compared to speakers) more easily from both the AVR and the sub end.

This shouldnt matter. Sure peaks relative to dips are higher or lower depending on what your volume is, but this changes all the time anyway depending on your listening level. Its for this reason a reference volume of 75db has been chosen as its the best balance to get a measurement from. Whatever your subs gain is at, the antimode should output a volume of 75 db during testing, which is why I assume you get the loud thud to begin with that then levels its self out. The antimode will then do its thing and once its set itself that is that regardless of your volume level at any given time.

You can then balance your subs to match your system and personal tastes. Of course, to be hearing the most effective results you should watch your films at the 75 db reference level too, which is why the volumes at the cinemas are always at this level (although I think reference level for them 105db?) and why its recommended by everyone from THX to Audyssey you view at the reference level

I think this is what Bazonix was saying but I figured I'd add this anyway.

 

[indus]

Hi Moonfly.

The two subs will be in different places. One will be at the front next to the L main speaker and the other in the back corner on the same side and near the sofa.

Can I just confirm my connection plan in my previous post is ok? My splitter plugged into the output hole of the antimode will do the same job as the Y cable that Bazonix describes?

Thanks

 

[Member 639844]

Yeah, its the same thing mate

 

[al_bert]

i emailed dspeaker with reference to this too and they told me as long as the anti-mode had calibrated the subs in tandem, its job is done. the user can then adjust the gains as required to achieve the right amount of bass

You can change the bass level from the AVR, or anything upstream of the Anti-mode. You can also change the bass level from the subs, as long as you adjust them in unison.

If you change either sub by a small amount, the change in the response won't be audible.

In the extreme case: what happens if you dial the other sub to 0? Do you need to recalibrate when you add or remove a sub? Am I thinking this the wrong way?

 

[bazonix]

hi do u mean dial the sub to 0 in respect of phase or gain?

 

[al_bert]

Its for this reason a reference volume of 75db has been chosen as its the best balance to get a measurement from.

I think you have misunderstood something. Anti-mode does not require a specific level, it uses whatever your sub is set to. It can perform calibration from quite a low level signal.

 

[bazonix]

You can change the bass level from the AVR

yes you can but its very important to keep the calibrated setting on the avr between -10 and -5db... any higher and the signal will not be clean.... lfe should be at max (0db) and then the only adjustments that can be made are from the sub itself.....

 

[indus]

Bazonix, which 2 subs are you running?

 

[Member 639844]

I think you have misunderstood something. Anti-mode does not require a specific level, it uses whatever your sub is set to. It can perform calibration from quite a low level signal.

Your misunderstanding what I mean here. I was talking about people like Dolby setting a reference level across the board on all devices, not the antimode specifically.

With regards the antimode this is what I meant. It seems to me the huge thud you initially get is a high spl signal for it to measure and then drop to a 75db level for taking a reference measurement. This can be done by the antimode regardless of what you set your sub to which is why it wouldnt matter if you altered the gain afterwards, as dspeaker say.

Thats how it seems the antimode works to me anyway. Perhaps someone can confirm this.