# Two Velo 12's or a single 15"?



## Bigdaddy999 (Nov 12, 2006)

Need a little help here. I'm upgrading my subs in a 4300 CF room with cathedral ceilings. Music sound quality is higher on my list than spl and slam.

I used to think I needed two subs, but having tried an HGS-12, I realize now that one better sub does way better than my two lesser subs and that part of my peaks/nulls problems were actually introduced by the old subs. 

Thanks to you folks, I got REW and set up to do some measuring The old subs tailed off from hi 20's and the Velo at 16. I've attached a trace of the two. Guess which one is the HGS...

No contest and the response curves bore out what I was hearing. Upgraditis has set in :bigsmile:



I'm hunting for a sealed servo sub solution because I like the sound.

I'm interested in your thoughts about one vs. 2 subs in this case. The two 12" velodynes have more cone area than a 15 and would have similar frequency response. Would there be a compelling reason to go with one vs. two subs in this case?

Thanks.


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## Sonnie (Apr 11, 2006)

I moved this to Home Audio Subwoofers... :T

Welcome to the Shack!

If you are strictly looking for sound quality and not SPL, and you are already getting the response you are getting with the one HGS-12, I'd keep it and add nothing else. You'll be money ahead.


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## JCD (Apr 20, 2006)

I'd second Sonnie's suggestion. I would generally go with a single better driver than two lesser drivers.

I will say that there are SOME benefits to having dual subs, but I think, for the reasons already stated, one would be better than two in this case.

JCD


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## Bigdaddy999 (Nov 12, 2006)

Thanks folks. I'm going to hang on to the HGS and see what happens. I KNOW I want a DD-xx, just cannot make it happen right now. I just have to say that the second HGS added a lot of punch..... Of course, that's the problem will all of this. there's always a way to do (er, spend) more. 

Now I'm wondering if the location needs to be rethought as well since the performance seems to be so different with the old to the "new" sub.


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## ACGREEN (Feb 23, 2007)

Starting from scratch, it is better sounds wise and budget wise to go with more, smaller subs. I have been reading a lot about 4 sub configurations. I am wiring my new theater for 4 subs. I'll be posting the results once it is set up.


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## Bigdaddy999 (Nov 12, 2006)

Well, I managed to borrow a DD-15 and I have to say, it's amazing in this room. one of those would take of me for life, but alas, it's not likely to happen. but WOW! Amazing piece of equipment and the DD's EQ process in different locations really shows why I struggle with this issue.

Someday...


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## Bigdaddy999 (Nov 12, 2006)

Sorry to bump this thread, but it's just about showtime on deciding on this.

I guess I'm leaning towards the dual subs simply due to the smaller, more flexible boxes. My recollection was that the dual subs filled the room more, but the dd-15 had the technical edge and tightness.

Am I missing something here? Will a single dd-15 outperform the dual HGS uncorrected with EQ? Staying with a single 12" HGS isn't going to do it, as I'm sure I'll overdrive it in this room.

tx


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## Sonnie (Apr 11, 2006)

No need to apologize for bumping the thread... :T

I suspect the DD-15 would be cleaner, but I probably wouldn't notice it myself. The dual 12's may provide more SPL and will give you the ability to experiment with placement to help with your response. Of course you could always pick up a BFD for 100 bucks or so.


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## Bigdaddy999 (Nov 12, 2006)

how about if I go with the second sub being a dd-12? would I be able to do eq using the dd to help even out the response from the two of them together? Seems like if the microphone is picking up the sound of both subs, then it might work? Can a DD do this?


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## Sonnie (Apr 11, 2006)

It gets extremely... and I mean extremely difficult to eq only one sub while measuring two. Generally you are always measuring both subs together, because that's what you are going to be playing is both subs at the same time. Generally if you make an eq adjustment, you do it to both subs, not just one. But hey, you could always try. I've tried adjusting just one and it was very frustrating not seeing the results move as I REW projected they would. I don't think the eq part of the DD would benefit you myself. Plus you are paying extra for the cleaner sub, but you won't really benefit from it since you have the HGS in the same room. I think you might be spending where you don't need to. :spend:


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## Bigdaddy999 (Nov 12, 2006)

i was thinking that if the microphone could pick up the combined signal and display it, then I could adjust the DD "manually" in order to deal with variations in response in the room. I think the DD's can only eq themselves, but manually, can you use the adjustments to conform a combined input to a flatter curve? IN other words, eq the DD first, then play both back with the DD mic and monitor response curves thru it (or via RS SPL meter and REQ)?


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## Sonnie (Apr 11, 2006)

You can do that, but it will be a challenge to ever get anywhere with it IME. Trying to deal with variations in the response by only adjusting one of the subs you are measuring is extremely difficult, or at least it has been when I tried it. You can try it though, I've just never seen many folks have much luck with it. It will most likely be a lot of trial and error to get it right, if you ever do get it right.


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## Bigdaddy999 (Nov 12, 2006)

Thanks Sonnie. Maybe I should just go for the single larger one. There's believers on both sides of this and I am so confused at this point that I'm not sure which route to go. I'm not all that excited about the BFD as another solution, but I'm 1/2 way towards the 2-HGS route and having doubts.


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## Sonnie (Apr 11, 2006)

Obviously I'm going to be bias towards the BFD + REW. I've not seen any combination of anything else that can do what these two products do when it comes to equalizing a sub... and they are very inexpensive... and there is plenty of help here in this forum for using both in conjunction with one another.

The BFD is going to be able to equalize much better than anything Velodyne has stuck on their subs... not to mention I wouldn't be all that crazy about using their eq's. Have you seen this thread... Behringer FBQ2496 / Velodyne SMS-1 distortion???

But lets back up a little... don't forget the issue you had with two subs. Look at that huge peak, which can be worked out easily with a BFD, but that null is a different story. If you go with dual subs, you really need to go with duplicate subs and co-locate them for the better response. It would be like having one sub box with two drivers. That 32Hz peak can be dealt with easily with the BFD... or you may not even notice it enough to worry with it.


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## Bigdaddy999 (Nov 12, 2006)

That 32Hz peak is from the single HGS-12 in the "preferred" position. I think the null was the result of issues within the other sub, NOT the room itself. The more challenging position is the RF main, which is where I was thinking about putting sub 2.

I have done traces with REW and it's not a big deal. I see people posting about the BFD "learning curve", so am a tad concerned about that. Is it correct that you hook up both subs to the BFD, and then you EQ each on independent of the other using separate EQ circuits within the BFD? I missed an ebay offer for a DSP1124 and another unit BOTH for $90.....


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## Sonnie (Apr 11, 2006)

Yeah... I agree... the null is produced by cancellation issues with the other sub, hence the preference to co-locate two identical subs.

If you can learn REW... the BFD is nothing. You can use the MIDI connection to load your filters via REW. However, it's possible you may not even need it. I would co-locate the pair of subs and run some measurements first.

No, you don't equalize the subs independently... that's what I was referring to above... it's almost impossible to do it. It's much easier to equalize them both at the same time. I have three subs... I equalize them all together and it works beautifully. No way I can equalize them each independently... it would be a nightmare.


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## Bigdaddy999 (Nov 12, 2006)

Thanks, Sonnie. I guess I had thought the BFD allowed you to set a curve for each sub you hook up to it. what you're suggesting is that the BFD must be used as a central EQ for the combination of subs you're doing, but they all get corrected against a combined input to the mic? Just like the sms, but without the GUI....?

In looking at the manual it appears to have 2 channels, so can you eq each channel independently?


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## Sonnie (Apr 11, 2006)

The BFD does allow you to do that, but it's just not the best method to use, as least not in my experience. The best method and easiest method I've used is to measure all subs combined and equalize all subs combined. It's truly much simpler. The BFD is quite a bit more flexible with filtering than the SMS... and REW is basically your GUI. :T


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## soho54 (Jul 22, 2006)

> In looking at the manual it appears to have 2 channels, so can you eq each channel independently?


You can, but as Sonnie has said it can get complicated.

The only time you would really want to EQ multiple subs independently is if they are running off different channels, or if the subs are locked into a fixed location and one just gives a terrible response in your favorite spot. I mean really terrible, so bad it hurts the total mix. 

If you have two pretty normal responses from them individually just EQ them together and save yourself a double/triple work load. Also make sure you take measurements from all the important sitting position in your room, and try to use the EQ to get a smoother overall room response. 

The one sweet spot gets old after awhile. Either you have to give it up to show off to other people, or you hog it and your friends aren't as impressed as they should be. :bigsmile:

Good luck. :T


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## Bigdaddy999 (Nov 12, 2006)

BFD purchased and on the way. Now to find that second sub.....! I'll be back for help, I'm sure! Thanks guys.


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