Which sub to augment my TN1220s

[Sorny]

Got a question for the HSU experts...

I have a pair of TN1220HO subs, each with a HSU 500W amp driving them at the moment. I have ample output SPL and low distortion (under 3% everywhere except 17.3Hz, where it's up to 8.5% THD according to REW at -15dB, which is my max listening level).

I started going down the rabbit hole with a MiniDSP 2x4HD, Umik-1, REW, and the like, and want to get the flattest response possible. My current results after EQ are pretty good for the sweet spot, but not so much elsewhere, thus I need another sub to flatten things out some more with less EQ needed.

What is the best match for both output capability and Frequency Response to my TN1220HO subs in the current lineup? I'm not looking for more output, even though I know I'm quite likely to gain output and lower distortion by adding another sub, I'm looking for what's the closest match to the TN's in sound quality, tuning, and whatnot to smooth my response in-room.

Current subs are located equidistant from MLP in back corners of the room. The new sub I'm thinking of getting is probably going to be located close to the MLP to even out some room modes at 23, 46, and ~90Hz.

[Kevin_Hsu]

Hi there,

We don't really have a sub that's very close to that in terms of performance. If you were to get another sub to run along, I would go with one that will either match or outperform it. In this case, the VTF-3 Mk5 HP would probably be the better bet.

[Sorny]

Originally Posted by Kevin_Hsu

Hi there,

We don't really have a sub that's very close to that in terms of performance. If you were to get another sub to run along, I would go with one that will either match or outperform it. In this case, the VTF-3 Mk5 HP would probably be the better bet.

So from a sound quality first standpoint, the VTF-3 is the best match to my TN1220HO's? Ok. So the inevitable follow-up question becomes, what would be the downside of going with a VTF-15 instead from a sound quality perspective, if any?

The price difference isn't enough to scare me, nor is the size & weight, because I've got 2 subs that a mere mortal can move without getting help. So, for the job at hand, which is flatter in-room response, the size & weight aren't big problems.
I know the VTF-15 will have higher SPL, which is low on my list of priorities, I know it'll play deeper, which is a bonus, but not critical, and I'd assume that when I gain match the subs, it'll play at lower distortion (as will the TNs). So, I'm just wondering if the VTF-15 wouldn't be the better buy unless you think there's a downside to the lower port tune and integrating it with the TNs?

You could make my life easier and re-introduce the TN1220HO mk2, just throw the VTF-2 driver in a 4' chunk of sonotube and you'd sell at least 1 pair today.

[Kevin_Hsu]

No downside in going with the VTF-15H MK2. As you stated, barring the TN-1220HO performance, the VTF-15H Mk2 will give you a bit more clean headroom and a little more extension. You do have to keep in mind that the TN may be the limiting factor as it would hit its limits before the larger sub would (bottleneck).

[Sorny]

All good Kevin, I placed my order tonight for a VTF-15H MK2. I suspected as much, in that the TNs should be a bottleneck... Not that I'm hurting in output or extension as you can see from the graphs.

I've attached some Room EQ Wizard plots after EQ, and before EQ showing that subwoofers placed 10' apart can still have great output summation. This is my 2 TN1220HO subs where I put them 16 years ago; one in each back corner of the room. Every room is different and all that, but if you've got dumb-luck like I did, you can see I was getting pretty good real-world in-room response/summation to start with. Yeah, there's some nasty nulls there because the real world sometimes interferes with our plans.

Red line is back left sub, green line is back right sub, blue is both at same time. The subs are gain matched, but I have no delay added as it makes overall response worse by some miracle of placement relative to listening position. I then saw the "natural house curve look" to it, and set a +10dB desired house curve in REW and it generated EQ filters that did what they said they'd do to give the REV 3 EQ graph after I imported the filters into my MiniDSP 2x4HD.

I did gain matching at -25dB, with both subs placed in the same spot in the middle of the room, and adjusted to 85dB. I must have had them placed in a null, or the tones generated by my receiver were at about 48Hz... I may have to use REW to see what the frequency of the subwoofer test tones from my receiver are at frequency wise now that I'm thinking about it.

I'm probably going to get the tape measure out and get the exact dimensions of the room and do some simulations to see where 3 subs gets the flattest response and try positioning subs there. I suspect it'll end up something like front left, back right, and somewhere on a side wall as best options. With only 1 big heavy sub to move (the TN's are featherweights and easy to move), it's not too bad. If I didn't have a fireplace in the front right corner, I'd likely have just done a sub in each corner much to my wallet's dismay.

Anyway, just wanted to say thanks for the advice, and wanted to show proof that even the older HSU subs are still quite potent. Oh yeah, I still want updated TN subs.

[Kevin_Hsu]

Originally Posted by Sorny

All good Kevin, I placed my order tonight for a VTF-15H MK2. I suspected as much, in that the TNs should be a bottleneck... Not that I'm hurting in output or extension as you can see from the graphs.

I've attached some Room EQ Wizard plots after EQ, and before EQ showing that subwoofers placed 10' apart can still have great output summation. This is my 2 TN1220HO subs where I put them 16 years ago; one in each back corner of the room. Every room is different and all that, but if you've got dumb-luck like I did, you can see I was getting pretty good real-world in-room response/summation to start with. Yeah, there's some nasty nulls there because the real world sometimes interferes with our plans.

Red line is back left sub, green line is back right sub, blue is both at same time. The subs are gain matched, but I have no delay added as it makes overall response worse by some miracle of placement relative to listening position. I then saw the "natural house curve look" to it, and set a +10dB desired house curve in REW and it generated EQ filters that did what they said they'd do to give the REV 3 EQ graph after I imported the filters into my MiniDSP 2x4HD.

I did gain matching at -25dB, with both subs placed in the same spot in the middle of the room, and adjusted to 85dB. I must have had them placed in a null, or the tones generated by my receiver were at about 48Hz... I may have to use REW to see what the frequency of the subwoofer test tones from my receiver are at frequency wise now that I'm thinking about it.

I'm probably going to get the tape measure out and get the exact dimensions of the room and do some simulations to see where 3 subs gets the flattest response and try positioning subs there. I suspect it'll end up something like front left, back right, and somewhere on a side wall as best options. With only 1 big heavy sub to move (the TN's are featherweights and easy to move), it's not too bad. If I didn't have a fireplace in the front right corner, I'd likely have just done a sub in each corner much to my wallet's dismay.

Anyway, just wanted to say thanks for the advice, and wanted to show proof that even the older HSU subs are still quite potent. Oh yeah, I still want updated TN subs.

Thank you so much for ordering our VTF-15H Mk2! Can you provide me with the room layout once you get the chance? I'd love to look over it and maybe provide some additional options for placement. So when you changed the speaker distance for both subs it made the response worse? That is interesting.