Calibrating 3 Subs

[William Lemmerhirt]

Get the 2x4HD. Iirc there’s a product comparison page on their site.

 

[Reckel]

I’m ordering another vtf3-mk5 tomorrow so I’ll have three now, the fourth one will have to wait for awhile. I assume I’ll have maybe the same issues as the guy who posted this thread?

 

[lovinthehd]

I'd get the 2x4HD for both voltage and delay advantages. Isn't it just user adjustable for input/output voltage tho?

 

[nbk13nw]

The 2x4HD is not adjustable. I had the same questions when I purchased mine. It is internal and as far as I know not adjustable.

 

[lovinthehd]

The 2x4HD is not adjustable. I had the same questions when I purchased mine. It is internal and as far as I know not adjustable.

Used to be you just flipped some switches on the board before....you sure that's not an option?

 

[NorCalRP]

I ordered the HD yesterday, along with the UMIK and a mic stand. The sub kit will arrive Thursday, so I should be ready to begin this project of building the 18" sealed Ultimax come the end of the week, then the real work begins

 

[NorCalRP]

Used to be you just flipped some switches on the board before....you sure that's not an option?

The input is selectable between 2Vrms and 4Vrms, but the output is set at 2Vrms

 

[lovinthehd]

Haven't dug into it for a while. My first mindsp output was limited to .9V, so of limited use. The second accommodated 2V which is generally fine. These days I'd just get the 2x4HD from what I've seen....just thought it still had limited output voltage capability.

The input is selectable between 2Vrms and 4Vrms, but the output is set at 2Vrms

 

[NorCalRP]

I personally figured the greater processing power and the upgrade path were worth the extra $100. I'm interested to see the impression of Diracs new iteration being rolled out at CEDIA. I think planning on using REW will be a great learning experience for me

 

[nbk13nw]

Used to be you just flipped some switches on the board before....you sure that's not an option?

It may be adjustable if I was to open the box. According to the manual you can configure the analog input sensitivity from 2 VRMS to 4VRMS. I have never cracked it open.

Edit. But as far as I can see you cannot adjust the output.

 

[lovinthehd]

It may be adjustable if I was to open the box. According to the manual you can configure the analog input sensitivity from 2 VRMS to 4VRMS. I have never cracked it open.

Likely you can, always a feature of miniDSP stuff.

 

[NorCalRP]

Hey @lovinthehd , you mentioned in another thread the potential gain from multiples, specifically that getting the subs with a quarter wavelength of one another produces a significant gain. At 20hz it's 14ft. In my room using the Geddes' approach, I know two of them will be within that distance, but am honestly not 100% sure about the third. Given that lower frequencies have even longer wavelengths, will a corresponding boost in lower frequencies occur with that third sub being further away?

 

[lovinthehd]

Hey I just quoted the acoustic info/formula. I can't promise what your room will bring, can only do the math....

 

[NorCalRP]

Hey I just quoted the acoustic info/formula. I can't promise what your room will bring, can only do the math....

Don't see the quote. Another thread ? I'm gonna feel like a dunce if it's one of mine!

 

[lovinthehd]

Don't see the quote. Another thread ? I'm gonna feel like a dunce if it's one of mine!

I meant about the 6dB gain from locating two subs within a quarter wavelength of each other....how about this http://www.sengpielaudio.com/calculator-coherentsources.htm

 

[NorCalRP]

I meant about the 6dB gain from locating two subs within a quarter wavelength of each other....how about this http://www.sengpielaudio.com/calculator-coherentsources.htm

Awesome! Thanks dude

 

[NorCalRP]

I've gotten my miniDSP hooked up, and have begun learning to measure response, create filters then export them to the mini, using the U-mik 1.

A question I have is this: what is the proper order of operations? I know sub crawls play into initial placement. When I begin to start measuring and applying filters, do I measure and apply each sub individually, then do a measurement and filter application for all 3?

I did get the Dirac Live upgrade for my mini, so I'm interested to see how that will play into the picture. With that, I'm wondering if the REW filters become extraneous.

 

[William Lemmerhirt]

Placement is always the first rule. I know there are different schools of thought so a couple thoughts are. @gene did as you asked, eq each separately then a global set of filters. I’ve seen that work, and also skipping that, and just globally filtering all 3. That’s what I did and seems to be more common. There IS a guide that gene made, it’s worth reading for sure. Maybe someone can link it.

 

[NorCalRP]

Placement is always the first rule. I know there are different schools of thought so a couple thoughts are. @gene did as you asked, eq each separately then a global set of filters. I’ve seen that work, and also skipping that, and just globally filtering all 3. That’s what I did and seems to be more common. There IS a guide that gene made, it’s worth reading for sure. Maybe someone can link it.

Thanks hermano! I look for the guide in the research section. Btw- I like your idea about inverting my PC-2000!

 

[NorCalRP]

So... I've been able to read a fair bit today. There's so much frickin info out there

I just finished building my Ultimax 18. It's sweet. I like it a lot. My measurements on the other hand... not as sweet. Modes up the yin yang. I know it's all fixable, so I'm happy about that.

Is it safe to think that a pair of ported subs can get me that low end output, and that 18 can fill in the midbass?

In my reading today I see that the most optimal way to handle things is to eq individually, then apply a global eq at the very end. Would that global eq be take a little away from the ported output as well as the sealed output?

At this point I'm thinking about getting myself to the best possible "starting point" by selling my PC-2000, a PB-1000 I have in another room, getting the dual drive VTF-3 MK5, putting the Dayton where my PB currently resides, and going from there?

Do I need to take crazy pills?