Definitive Tech. Bi-polar question (1 Viewer)

[murpharmd]

Hey folks,

Was at a local shop the other day listening to the new Def. Tech bi-polar series (8040 system). Liked the sound, but not a fan of the price. The salesman said he had 2 of the older model 7006 series in stock, but both were right speakers. He said this shouldn't be an issue because the only difference between a right and left was the direction that the subwoofer was firing and that this shouldn't hurt imaging/output.

After thinking about this it did make sense that this may not be an issue because the sub puts out low frequency which would produce multi-directional output.


Am I right with this line of thinking? I guess the LF output could be affected by your room set-up if you had these BP towers firing in the same direction, but I don't think this would be a problem with my set-up. Anyone have any input on this?


Thanks

 

[David Willow]

Sort of.


Anything below about 80hz is hard to locate. If the 'sub' portion of these is crossed over below 80 hz, then it should be fine.


My question to you is why do you want floor standing surrounds with built in subs? The sub should be separate from the speakers since it needs to be located differently for proper sound. Subs built into any speaker is a waste (or even a gimmick), IMO, but especially in surrounds.


What other equipment do you have in your theater?

 

[murpharmd]

Thanks for the response David. Are you asking if these would be used for surrounds in my system? These would actually be used for fronts. I thought these would be a good idea given that I wouldn't have to worry about trying to find the right placement for a separate sub. This system is going in my basement, which has some weird dimensions.


I am currently researching potential systems, so I don't have any of the components yet. I am looking at the Marantz SR5005 for the receiver, the Def Tech BP7006's for the fronts, Def Tech CLR 2002 for the center, and either a pair of Mytho's Gem's or BP1.2x for the rear's. I currently own Paradigm's (3.1 system) that are used in the living room and have been looking at the Paradigm Millenia series. I have very limited resources as far as being able to audition different brands. Have to drive at least an hour to an hour and a half to get to the closest retailer (want to use a local shop instead of big box store).

 

[Mark-P]

Oh come now David, you do understand that each discrete channel in a 5.1 soundtrack has frequency extended all the way down to 20hz, right? Ideally having 5 tower speakers capable of 20-20000hz would be the ultimate, but hardly anyone can afford that, so most of us compromise by buying smaller speakers and directing lower frequencies to a single sub-woofer.

Originally Posted by David Willow


My question to you is why do you want floor standing surrounds with built in subs? The sub should be separate from the speakers since it needs to be located differently for proper sound. Subs built into any speaker is a waste (or even a gimmick), IMO, but especially in surrounds.

 

[David Willow]

Mike, front speakers should be pointed directly at the listen(s) for the correct effect. Bi-Polar will not work well in the front.


Mark, are you saying that the best place for the sub is also the best place for the speakers??? Very, very rarely is that ever the case (if ever). So I disagree 100%. It is never best to have full range speakers, regardless of budget. Instead, if money is not a problem, get 4 subs and locate them properly.

 

[murpharmd]

David, these would be pointed directly at the listening/seating position(s). This BP model is a tower unit with a front firing array consisting of a 4.5" midrange and a 1" aluminum tweeter, and also uses the same array pointing to the rear. The subwoofer is located at the bottom of the tower and is coupled to two 8" bass radiators. The subwoofer is side-firing; so in this case the subwoofer in each tower would be firing in the same direction.

So, getting back to the original question; would having these subwoofers pointed in the same direction be an issue?

 

[David Willow]

I believe it will work as described by the sales guy.

 

[Al.Anderson]

I didn't do a lot of research on these speakers. But I don't think using two 'rights' is a good idea. For one thing, they wouldn't make a right and left if it didn't matter. Secondly, these towers have 1", 3.5", and 8" drivers. The 8" server as the"sub". Not only is an 8" driver not well suited for a sub, but a 3.5 inch is not well suited for bass. So I'm thinking that the 8" also performs bass duty, which is not non-directional.

 

[murpharmd]

Originally Posted by Al.Anderson By Series|BiPolar Series&productid=BP7006

The third sentence in the paragraph at the bottom of the page talks about placement of the subwoofers either toward or away from each other. So it looks like "room tuning" could be an issue.

 

[Earstoyou]

Hi Mike,


I encountered this exact same question about a pair of "left" Def Tech BP7002's I am buying. This week, I spoke to Chet in Tech Support at Def Tech (very friendly and helpful - not surprising, as I had read before how great their customer service was), and he definitively (LOL) said that this will not be a problem in any way, and that the new speakers they make no longer are identified as left or right, since it is an audio non-issue. My neighbor, who installs audio and AV systems in the mega-buck audiophile/videophile range also said that this is fine due to the non-directionality of low bass, and he likes the bi-polar design very much, and thinks highly of the sound of the 7000 series, as I bought mine based on his direction in upgrading my B&W 601 S2 fronts. He said all the 7000 speakers are great as fronts, either for movies or music. The only issue I myself see is possibly scaring someone off in the future in reselling them, in that others will not be aware of the non-issue of having 2 lefts or rights.

 

[Al.Anderson]

Maybe its a case of knowing just enough to be dangerous - or in this case just enough to be suspicious, but I'm still not convinced.


I still feel that the driver sizes are working against you. Low frequencies become non-directional at around 80Hz. That means that for the 8" driver on those speakers to be non-directional they have to be handling only the sub bass frequencies. An 8" sub is not one you'd spend a lot of money on or expect to fill a room. Continuing down this same line of thinking, if the 8" is playing just the sub-frequencies, that means the true basss and mid-range is being directed to the 3.5" driver. That size speaker is not ideal for either of those frequencies. So, assuming the claim of non-directional "right" and "left" speakers is true, it means you are getting non-optimal performance - it seems like a gimmick.

On the flip side (and the one I actually believe), if the 8" driver is playing above 80Hz, then you would get better mid-range production, but they *would* be directional; so you'd lose performance off-axis.

 

[Earstoyou]

From the Def Tech website:


"Each BP7006 combines a built-in 8-inch subwoofer driven by a 300-Watt class D amplifier and two pressure-coupled 8-inch Low Bass radiators for 150 square inches of bass radiating area per speaker! That’s nearly as much surface area as a single 15-inch woofer but with better control, speed and detail than a single big woofer could ever deliver. Built-in powered subwoofers achieve dramatically better blending, integration and timbre accuracy than could ever be achieved with separate subs.


Each BP7006 features front and rear mounted driver arrays each consisting of one high-definition cast-basket 4-1/2" bass/midrange driver and a 1" annealed Pure Aluminum dome tweeter. Linkwitz-Riley crossover networks do a superlative job of seamlessly blending the drivers for totally homogeneous sonic output as if radiating from a full-range pulsating sphere."


IMHO, I think it is the fact that the two 4 1/2" drivers together perform quite differently than simply one alone. The much maligned Bose 901s have I believe nine 3" drivers, and additively they produce their (Bose's) version of bass, which is not deficient, as I have owned those speakers myself. Why debate the theory, when listening will tell you if it works or not?

I have a single BP7002 in my living room awaiting delivery it's identical twin, and even alone, I can tell you that the bass is almost as strong and as tight as my 12" stand-alone sub, and putting it's twin in the mix will no doubt bring it fully up to suitable bass-producing levels. My audio pro neighbor came by, we put the receiver on mono, and compared the one 7002 alone to one side of my B&Ws with the sub, and he thought as-is, the sound was great. The 7006 is obviously smaller, but he still says it is a very good speaker that gives real-world sounding presentation.


The reviews at Audio Review are also helpful, as owners will detail the speakers' actual performance in their homes.

http://www.audioreview.com/cat/speakers/floorstanding-speakers/definitive-technology/bp7006/PRD_324160_1594crx.aspx


I know that this still does not address the question of 2 same-firing subs, but why not call Chet at Def Tech and ask him to explain why it would work? He has no incentive whatsoever to tell you wrong info on used speakers, right? I know from my own experience how frustrating it is to try to get these expenditures right so that we are not wasting hard-earned cash and will still get the improved sound that we are looking for, but my own opinion is to take a calculated leap of faith and trust certain folks who do this for a living, but have no financial stake in my decision. Just my humble 2 cents.

 

[Al.Anderson]

>> I think it is the fact that the two 4 1/2" drivers together perform quite differently than simply one alone.


On the theory side of things, one of the 8" drivers is a passive radiator; that's not nearly the same as having two driven cones.


>> The much maligned Bose 901s ...


It pains me to say anything good about Bose, but actually, the 901s may have been their last good speaker. Of course, that was 30 years ago.


>> I have a single BP7002 in my living room awaiting delivery it's identical twin, and even alone, I can tell you that the bass is almost as strong and as tight as my 12" stand-alone sub ...


That works for me. If it sounds good then that's what matters.


>> I know that this still does not address the question of 2 same-firing subs.


I forgot to mention this, but if the 8" are really working at the sub-bass level, this would be the one positive, you'd wind up with dual subs. (At the expense of giving up mid-range.)

>> ... but why not call Chet at Def Tech and ask him to explain why it would work?


Not nearly that invested (there's zero chance of my getting those speakers). Taking wild-ass guesses on a forum is easier and so much more satisfying!

 

[murpharmd]

Thanks again for the response guys.


Bob, I did contact Chet at Def Tech and he said pretty much the same thing he said to you. I went ahead and ordered the speakers and received them this week. I have yet to power them up (waiting for receiver, but may hook them up to my old Denon in my living room to make sure they are working and to see what they sound like). I listened to these last summer and really liked them, but at that time I wasn't that close to getting my basement finished and the price was just a little too high for my wife's liking. I got a nice price on them and they are brand new. I will let you guys know how they work out.

 

[Earstoyou]

Hey Mike,


Congratulations on your 7006s! If they can (in their price class) impress my neighbor Peter, who has heard and installed Wilson, Dynaudio, Revels, Sonus, B&W, Snell, Magnepan, etc., then I can only assume that they must be pretty good, as I think he has quite a good ear. He said that bipolars absolutely can be used as front speakers, as this is their main use. I hope to hear from your next posts how they end up working for you. Good luck and happy listening!