Powered Towers Question (Older Def Tech)

[TwoCamSam]

Hi All,
Been browsing this site for quite sometime and have watched a lot of Gene's videos. I'm not a newbie to HT/2ch, but I'm certainly no expert in getting my equipment to sound as good as it could. Trying to get there though. I feel that I have a pretty decent setup (but it could always be better, right?!), but I'm getting the itch to dive deep into what some of this stuff means and how it works.

Here is a quick overview of my setup (3.1)
Yamaha RX-A1080 AVR
Def Tech ProTower 400's powered towers (produced late 90's early 2000's)
JL Audio E110
Crappy Def Tech center.

So, it seems like there are 15+ different ways to setup these "powered towers." My real question is, if I set my speakers to small and crossover at 80Hz, do I HAVE TO have the powered towers plugged into wall outlet? I know Def Tech says always must be because of electronic crossovers, etc.

I get this defeats the purpose of having a "powered tower", but right now its all I have, I don't have a budget to buy new floor standing speakers, and really just want them to perform like a passive speaker just hooked up with the speaker cables.

I'm about to rewire my setup (which is in the living room, not dedicated, so aesthetics to come into play with the wife). This would eliminate some unnecessary cables (trying to reduce as much as I can). Reduce some amperage load on the circuit. (I've never tripped breaker a or anything, but I have a fairly loaded up Panamax which runs off a single outlet in the living room[which is also wired to other outlets on the circuit])

If they are OK to run without the AC power, I assume set to Small at 80hz is still the best setting on the AVR. I get the two powered woofers in each tower can a bit of bump and smoothness, but honestly the JL gives a pretty good punch and seems to integrate well on its own. Looking to add a second E110 before floor standing speakers are replaced as well.

Thanks for any advice!

 

[ParisB]

Yes, you still need to plug them in so the speaker uses all its drivers, even if you set a crossover to roll it off (not a brick wall). The woofer in the newer DT's starts activating at about 125hz so I'm assuming the older ones are similar.

 

[Pogre]

Yeah, DefTech probably crosses over to those powered bass sections a lot higher than 80 hz so you'll be missing some frequencies if you don't plug the towers in.

 

[TwoCamSam]

Ohhhhh. I think I see what you mean.

So, even if it has no power, the tower internal crossover is still filtering around 125hz to the mid/tweeter sections, and the AVR is set to 80hz, there is still nothing active in the tower (with no power) to fill the gap between 80 and 125hz?

If that is the case, could you in theory set the AVR crossover for the front L/R 125hz and let the JL pickup the gaps, or is it just going to sound awful trying to let the sub fill 125hz down all the time? Prob not good for it long term either?

 

[Pogre]

Ohhhhh. I think I see what you mean.

So, even if it has no power, the tower internal crossover is still filtering around 125hz to the mid/tweeter sections, and the AVR is set to 80hz, there is still nothing active in the tower (with no power) to fill the gap between 80 and 125hz?

If that is the case, could you in theory set the AVR crossover for the front L/R 125hz and let the JL pickup the gaps, or is it just going to sound awful trying to let the sub fill 125hz down all the time? Prob not good for it long term either?

Yup. You got it now. Your understanding is correct. Some subs are capable of being crossed over that high but you run into issues with localization. In other words if your sub isn't located right by your main speakers you'll be able to localize it by ear and can tell the bass is coming from a different source. That's why 80 hz is the rule of thumb for crossing over to a sub. Below 80 hz we lose the ability to localize where the bass is coming from.

 

[Eppie]

The E110 is rated up to 116Hz +/- 1.5dB. Probably goes a little higher but you need to see the frequency response graph to know the roll off. Crossover on the sub goes as high as 130Hz. The problem is you don't know where the subs are crossed on the Def Tech. I couldn't find any detailed specs but that's not unusual in that price range. The Def Tech archive does not go back that far either. You won't harm anything running them passive but it's hard to know whether there will be a gap in the mid bass without taking measurements. You'll likely be relying on your ears alone.

 

[Pogre]

The E110 is rated up to 116Hz +/- 1.5dB. Probably goes a little higher but you need to see the frequency response graph to know the roll off. Crossover on the sub goes as high as 130Hz. The problem is you don't know where the subs are crossed on the Def Tech. I couldn't find any detailed specs but that's not unusual in that price range. The Def Tech archive does not go back that far either. You won't harm anything running them passive but it's hard to know whether there will be a gap in the mid bass without taking measurements. You'll likely be relying on your ears alone.

I wouldn't be surprised at all of the mids cross over to the bass section at well above 120-125 hz, tho you're right it's hard to say without some more detailed specs. It does look like the JL sub's upper limit might not be adequate for what op is wanting to do.

 

[ryanosaur]

@TwoCamSam
JC... Is there a reason you do not want to plug them in? Is it convenience, power draw, something else?

 

[TwoCamSam]

Yup. You got it now. Your understanding is correct. Some subs are capable of being crossed over that high but you run into issues with localization. In other words if your sub isn't located right by your main speakers you'll be able to localize it by ear and can tell the bass is coming from a different source. That's why 80 hz is the rule of thumb for crossing over to a sub. Below 80 hz we lose the ability to localize where the bass is coming from.

Thanks for the info! Right after I submitted my last reply I instantly thought I'll bet a 120Hz tone out of the sub is going to be very "localized." Also, I didn't actually realize 80Hz was the frequency where we start losing the localization. I had always heard start there and that's what THX recommends. I don't think I knew that was where the localization drops.

@TwoCamSam
JC... Is there a reason you do not want to plug them in? Is it convenience, power draw, something else?

Convenience is one for sure. Lots of cables running on the floor at the moment and I'm about to rewire and remove anything not being used (Powered Towers are power, speaker cables, sub cable for the LFE at the moment). My thought was, I really don't NEED the additional bass from the towers. The E110 packs a solid punch, but I would like a second one soon just to fill the null areas. I get the current woofers in the towers can help now, but it doesn't seem to help that much.

I'm concerned and not concerned about power draw. I do have a Panamax that is pretty loaded up. It also runs on a living room outlet which is connected to others. I've had it running for almost 2yrs like that without issue, but when I really think about all of that equipment pulling through a single outlet that's not a dedicated circuit, makes me a bit uneasy. I'm sure the Yamaha AVR and JL E110 suck enough by themselves.

 

[Pogre]

I personally wouldn't want to run them unplugged. I think you'd notice it. It wouldn't hurt anything to try it out right now tho. Are they still set up? You could unplug 'em right now, turn your crossover up as high as it'll go and see if it works for you.

On the plus side everything I've been reading about your speakers is pretty positive. It's one of their few powered models that aren't bipolar speakers. They're older but older doesn't mean "not good" and by all accounts seem to be well liked. So you do seem to have some pretty good speakers and it'd be a shame to hamstring them by not running the powered woofs.

Maybe start looking through the classifieds for some non powered speakers and repurpose or sell the ones you have now. You should be able to get a couple hundred bucks for them. I'm always looking through Craigslist and if you're not in a hurry you can stumble across some great speaker finds. I see Infinity IL40s pop up from time to time for $150 ‐ $200 and they're really great speakers. I'd say on par or better than the ones you have now.

That's the IL40. Not the IL60, which is also a powered speaker. The IL40 is not powered. Anyhoo, yeah. Craigslist can be pretty good for speaker shopping.

 

[ryanosaur]

I'll bet a 120Hz tone out of the sub is going to be very "localized." Also, I didn't actually realize 80Hz was the frequency where we start losing the localization. I had always heard start there and that's what THX recommends.

You are misunderstanding what Pogre said.
Most people will say that localization is around 120, not below... Some will claim they can start identifying the Sub as a source around 110...
But there are just as many people, if not more, that are crossing their gear up around 100.
80Hz is usually the most common point to cross at with some insisting that you get a better blend going higher.

Regarding the other point, I would argue that you should plug in your Towers, as much as I dislike DT, and do awat with the LFE connection. Rather connect for Speaker level input only and cross Small somewhere around 80 to 100Hz.

This will likely give you the best opportunity at quality sound reproduction.

 

[Pogre]

Most people will say that localization is around 120, not below... Some will claim they can start identifying the Sub as a source around 110...

I gotta be honest, I might be misunderstanding localization too and be in need of correction. Is localization the point where you can hear the sub standing out or the the point where you can pick out its location in the room if it's not by your speakers?

 

[lovinthehd]

I gotta be honest, I might be misunderstanding localization too and be in need of correction. Is localization the point where you can hear the sub standing out or the the point where you can pick out its location in the room if it's not by your speakers?

Bit of both I believe, so it varies with room/placement/speakers/subs/crossover slopes all kinds of fun stuff. Personally in my multiple sub setups I can easily cross at 120 without localization but have had issues with a single sub at even 80 in one setup. Some discussion in this thread

 

[ryanosaur]

I gotta be honest, I might be misunderstanding localization too and be in need of correction. Is localization the point where you can hear the sub standing out or the the point where you can pick out its location in the room if it's not by your speakers?

Localization is the point where you can identify the source of the sound, at least as I understand it as it applies to Subs.

My suspicion is that this will not only be somewhat individualized by listener, but may also have to do with room size and how much reflection of low frequencies is actually happening. (Consider a small 11x15' room vs a 21x45' room where in the later, some of those frequencies will have a chance to fully propagate before reflecting.)