Axiom Home Page Forums General Discussion Stereo Looking for a sub to mate with M3Ti and NAD

I have M3Tis being driven by a NAD C320BEE (with C542 for CD source, and soon to hopefully be a Rega P2 through a NAD PP-2 for vinyl with an eventual preamp upgrade). I've not heard the M22s much but overall I like the warmer midrange sound of the M3s and the smooth detailed response they have when mated with the NAD...

But now I want to extend and improve my bass a little. Without a dedicated sub out and crossover options I'd really like a sub that had high-pass options to control what bass the M3s will be responsible for but I'm not sure how necessary that will ultimately be.

I've looked at the HSU STF-1 and the Outlaw LFM-2 as a couple possibilities. This is going in my bedroom which is about 12x14x7 or so feet and more importantly I'm on a budget as a graduate student and would like to keep it under $500. I'm not looking for tons of bass, I listen to rock mainly (classic and new) and just want to enhance my bottom end a little.

I've seen a lot of threads on the topic, most say the M22tis are better when matched with a sub. I found them a bit brighter than the M3s so I'm hoping to find a nice balance that will compliment the M3s well.

This sub doesn't have the high pass you are looking for but it is an incredible value. My son has one in his bedroom and it does a wonderful job for him.

BTW the Hsu and Outlaw subs doesn't have high pass either.

Sorry, I should have mentioned that I realized none of those subs have high pass, and I may not be so lucky in my budget. I don't know how absolutely necessary it is, given that the M3s are quite capable of handling the bass load it may not be so bad leaving them as they are currently.

I've looked at that AV123 sub briefly and have considered it as well actually. Currently I'm probably most interested in the Outlaw sub of the three (it's essentially a revised STF-1 by Dr. Hsus own word).

This is a combination M22+x-sub I'm thinking about to install for upstairs, mainly for stereo listening. I wish I could listen to it before buying. On the other hand, what have I got to loose? I can always ship it back. Anybody knows about how good AV123 return policy is?

From my understanding they are on par with Axiom. That would make for a sweet set up Gena.

Hmm it really seems those remain the three main recommendations in that price range in spite of the lack of high pass filters.

I just wish I could read more on the AV123 X-sub and get some more feel for it from reviews. I know the HSU and Outlaw are both good subs.

All have good customer service reps. Good quality reps ... price or look might be the decider if it were me.

Another sub I've read up on some is the Mirage S8, $200 from amazon and seems to be reasonably well liked. As a brand I'd be more trusting of Outlaw or Hsu though.

No rush, if anyone's got some input I'd love to hear it. I'm tackling a turntable first.

The STF-1 sounds like a really good bet for your needs. Even the STF-2 is under your $500 budget. You could email Hsu and see if they have any b-stock models available.

Have you looked at the AV123 Outlaw Rocket ULW-10 (499.00)? I am looking at a M2i w/ the Rocket UFW-10, but I will not be able to comment for them for about 4-6 weeks (lead time for custom wood M2i's).

I'm not sure if you've read it yet, but Craigsub did a review of the x-sub over at the av123 forums - link
I'm thinking of getting one as well for apartment living and then eventually in some sort of 2 channel or computer setup.

You may want to look at this by Rocket. Link

Thanks so much for the x-sub review link. It looks awesome!

The X-dub was getting me really interested but I really don't want to deal with the auto-on problems it apparently has.

I've been running the x-sub for about a month now, and I haven't experienced the auto on problem.

The auto-on problem only shows up if you use the high level inputs and listen at moderate volumes. I only plan to use the RCA inputs so it should be fine for me. What size room do you use the X-Sub in?

Strangely enough, I use the high level inputs and listen at moderate levels! Soon, I hope to change out some gear and use the RCAs, and I can see if there is a difference. My room is roughly 11 1/2 X 11 1/2.

There does seem to be a bit of lag time when using the high level connections with the xsub. It doesn't seem to be too bad to me. I hope to change it over to the low level connections tomorrow when I pick up a Nad intergraded amp.

The lag time is hardly noticeable, at least to me. It's weird, but when I first got the sub I needed to turn the volume way up before it detected a signal. Now, everything seems fine and it gets a signal even at lower levels.

Now that I think about it, it may be the fact that I'm not constantly peeking behind the sub looking for the green light. After I sit down, I usually don't get up!

Which NAD are you getting? My only choice with my NAD integrated amp is to use the high level speaker connections to the X-sub.

Even still, I've got a couple mentions in here of no trouble with the auto-on to a whole lot over on av123. Sure you generally hear more negativity on the internet about an item as opposed to whats good but I've heard a lot of both and AV123 is internet direct so I'm still feeling an overwhelming majority of people are having issues with it.

I may order it anyway and try it out and see how it does. If it works I'll keep it. If not it can go back to the mothership.

It seems to be a problem they are working on over at AV123. You may want to give them a call during the week and talk to someone about it. They have great customer service, so it's definitely worth a shot.

I'm doing research for a purchase that could be 3 weeks away or 2 months away. If it hasn't been resolved by then I probably will call them and see what's been going on with that. For $200 I can probably swing it any time soon and give it a trial but I'm trying to get a turntable first which is a bit more of an investment.

Well I went and picked up the Nad and come to find out it was a receiver not an integrated amp. So it's only high level connections here. I did get it set up with the B&W D10s and it sounds pretty darn sweet.

Speaking of turntables I also picked up a Denon DP-37F in excellent condition. The deck on this thing is a beautiful rosewood finish. Does anyone here know anything about these units?

The HSU STF-1 has high level in/out and is only $299. I have the STF-2 and it is spectacular.

Wid, are you sure about that? The integrated amps don't have any sub out, at least not the 320 and I don't think the others do either. The receiver would be more likely to.

danmagicman7, that's why I'm considering the Outlaw LFM-2. My friend has the HSU STF-1, and it's a good sub. The Outlaw was also designed by Dr. Hsu and he believes it should be a lower distortion design compared to the STF-1 but it is still very very similar to the STF-1 from HSU.

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Wid, are you sure about that? The integrated amps don't have any sub out, at least not the 320 and I don't think the others do either. The receiver would be more likely to.

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I didn't say the 320 would have a "sub out" but there is a way to use the low level inputs of the sub with the 320.

The receiver I picked up today was an older unit, the 7120.

What way is there?

With some subs you can run a preamp loop (I assume you're talking about doing that) but I don't believe any of the ones I'm interested in provide that option. If they did I'd probably go that route rather than high level.

All you have to do is split the preout signal of the preamp section and send the signal to the amp of the sub and back to the amp section of the 320.

I use these for the job.

Hmm that should work shouldn't it? Thanks for the suggestion.

That's another point for the X-sub then since it has low level inputs and the Outlaw LFM-2 does not.

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The Outlaw was also designed by Dr. Hsu and he believes it should be a lower distortion design compared to the STF-1 but it is still very very similar to the STF-1 from HSU.

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Unless your freind has done a side by side comparison of both subs there is no way he can qualify this statement.

It will work, no doubt about it.

by he I mean Dr. Hsu

Carl, you were interested in a high-pass to the M3s. Note that if you use a loop on your 320 such as Rick Widner described, you can also insert high-pass filters such as these into the loop.

Oh my, thank you! I never knew such an option was available. I had seen some variable ones but they cost more than I really wanted to put in to this right now.

So Dr. Hsu told you that Outlaw makes a better sub............interesting.

Thanks for providing another alternative, John. I had been looking at these from ACI and was wondering if there were any other alternatives. It looks like the cost is relatively the same.

John, do you have any experience using such high pass filters? Just curious about how they work and sound.

Let me restate it... as presented somewhere in documentation on the web that Dr. Hsu designed the STF-1, and then redesigned it and that is currently being produced as the LFM-2 by outlaw, but I wouldn't be surprised if it's being made by HSU. Whether you choose to believe that or not isn't an issue to me, but it's an interesting statment true or not. If I were going to order either the Outlaw or the HSU I'd order the Outlaw and give it a comparo to my friends HSU. I suspect they'd be similar, they use the same overall enclosure (port relocated to bottom on outlaw), same plate amp and same driver.

Either way from what I've been told he has apparently designed subs for others in the past.

I know it is a fact that Hsu helped with the design of the Outlaw subs, there no questening that. I just thought it was an interesting statement that Hsu would say the Outlaw sub would be of a lower distortion design.

Sean, I've been aware of the somewhat similar ACI filters, but I suggested the Harrison Labs items instead because they indicate a 12dB/octave slope rather than the 6dB/octave of the ACIs. This apparently means that they use a second-order filter with a series capacitor and a parallel inductor rather than only a series capacitor which forms a first-order 6dB/octave filter.

Have no personal experience with either one. You might take a look at the Harrison Labs site, especially page 2 of the catalog where it shows how the varying amplifier input impedance affects filter frequency. I'd noted that Carl's 320 has a 20Kohm input impedance, so the result should be essentially the same as the 22Kohm designed spec of 70Hz.

You might also take a look at page 3 to read a complimentary comment about it from Absolute Sound. Note however that some audio enthusiasts would probably(with a touch of paranoia)reject these filters out of hand because of the "cheap" capacitors and inductors used. I recall an incident from about three years ago when Ian participated more frequently when someone indicated to him that he'd been disturbed on seeing the caps and inductors in the Axiom crossover and had the affrontery to suggest that "quality" replacements be made. Ian of course politely replied that the components had been thoroughly tested to provide optimum performance and that no replacements were necessary.

A brief comment on the STF-1/LFM-2 comparison being discussed here: have no idea about "lower distortion", but as I've indicated previously, the LFM-2 has a greater rated bass extension, possibly because the different port location allowed using a slightly longer tuning tube. This would result in a lower extension, with slightly less maximum output higher up, which some might consider to be a reason to slightly prefer the LFM-2.

Thank you, John. From my limited understanding of slopes, I was under the impression that the steeper the slope the better--meaning the overlap of the sub and the speakers is kept to a minimum. The 6dB octave filter may seem too steep. I don't even know if my understanding is correct, though.

I'm going to have to read up on second-order filters.

These high-pass filters seemed such a simple thing at first. Who'd of thunk I'd actually have to LEARN something before buying!

At 20k vs 22k it should be relatively close and I can simply adjust accordingly. I am however interested in what the quality of those crossovers is. I would probably intend to try first without them however.

Sean, it's the other way around; 6dB is the least steep. Generally, steeper is better(except that some audiophiles make a fetish of preferring 6dB first-order crossovers), and the THX specs for receiver crossovers call for a 12dB/octave high-pass to the speakers and a 24dB/octave fourth-order low-pass to the sub.

Again, thank you, John. Looks like I've got some reading to do. I've never really bothered that much with subs. For HT use it seems a bit easier where the receiver does the work. Two-channel stuff is a bit more work.

Right now I'm looking in to cable options instead of buying a hard splitter like that. Perhaps a RCA-M to RCA-F/RCA-M cable with a short length which would simplify connectivity. I'm looking at DIY as well as custom order, I know Cobalt Cables can do it for me as I had a nice talk with one of their guys on phone and via email. He expressed concerns about signal degredation, which I have but I am willing to try it. The cost for two such splitter cables built by them at a length I specify is pretty much the same as buying the splitter and similar quality cable but a much neater option so I'm considering it.

I'm also considering DIY but after adding up everything I'd need that may not work out to be cost effective. It appears there isn't any rush, the subwoofer is out of stock right now anyway.

Ultimately I'll probably try the X-sub with my zany RCA-M to RCA-F/RCA-M splitter idea and a couple of those 70Hz high pass filters. Not particularly expensive and it'll be interesting to try.

edit: nevermind the black one isn't sold out until June, the light maple one is. I'll probably be waiting until June anyway.

Carl, there doesn't appear to a good reason to make this more complicated or expensive. Regardless of what Cobalt said there's no appreciable "signal degradation" that'll occur over a few inches of wire and no need to be concerned about the "quality" of the cable. If you get the filters from Parts Express, the simplest and least expensive option for cable-type splitters, if you prefer that, would probably be to also get a couple of these from them.

Yeah that's the other option. I'm just having some fun looking at different things.

I am actually looking at getting that from bluejeans cable if I go that route for the slightly better build. I've had probelms with some of the cheaper parts express cables wearing out on me if I'm reconnecting them. I'd like something a little more robust... and the Cobalt Cable isn't much more than the BlueJeans cable but would give me a cleaner cable arrangement.

Depends on how much my tax return is. Haha.

Whom ever you get the splitter from make sure you get one that has one male end into to female ends. This one made by Dayton is a pretty robust cable, no need to worry about it "wearing out" and it's pretty inexpensive to boot.

I've used both kind, the hard splitter and the cable type, with no suffering of sq that I could tell. John is right imo that it is an unnecessary worry to think sound will be affected by either type.

At this point I know what cables I need, it's just a matter of how I want to arrange the setup.

Unless that high pass filter is male-male (and they aren't) I need two males and one female on the splitter cable. Males for the preamp out and amp in and female for the other RCA cable I'll be using to hook up to the sub.

edit: Unless you are thinking the sub needs a single RCA input. It does not, the X-sub has stereo low-level inputs which should be fine for this.

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Unless that high pass filter is male-male (and they aren't) I need two males and one female on the splitter cable. Males for the preamp out and amp in and female for the other RCA cable I'll be using to hook up to the sub.

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Look I am just trying to help. I don't know what type of cabling you're thinking about but the way I figure is you need as I stated above.

From the preamp out you run the splitters (two of them) to the left and right with the male ends (like I linked to) from the female ends ,two of them for each splitter, you run the interconnect cable left and right back to the main in on the amp section of the Nad. You can insert the hight pass filters directly to the main in.The other female ends you run left and right sub cables to the amp of the sub.

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Unless you are thinking the sub needs a single RCA input. It does not, the X-sub has stereo low-level inputs which should be fine for this.

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You need not tell me what the X-Sub needs, I own one.

Haha that makes it more confusing. A splitter with two female and one male would work but necessitate more cables. At the moment I'm pondering this setup if I'm feeling goosey.



obviously x2 for both channels