Speakers with self-powered subwoofers - yes & no

[Boomzilla]

Stumbled across these today:









FIRST IMPRESSIONS:

These are NOT flat. They have a "boom & tizz" sound reminiscent of the 1970's JBL line. Crank down the bass & the speakers sound thin. Crank up the bass and they sound boomy. Is this an artifact of the speakers or the room? I can't say definitively (sorry, I couldn't resist...). I tried moving the speakers closer to & farther from the back wall. I tried moving the speakers closer & farther from each other. I tried toeing the speakers in & out. I never quite got the bass to completely focus. Despite this, I wouldn't call the bass bad at all, just not the best I've ever heard.

Also, despite the "position dancing," I never got the image to "snap in" like it does with my Deftech SM65 speakers. The image isn't bad either, it just wasn't great. I need to get Garbulky over here and put his educated ears to work.

The major problem with these speakers, to my ears, isn't the bass or the image; it's the frequency response. The speakers have either a crossover artifact or a peak in one (or both) of the drivers' frequency responses. It's at a frequency that makes some female singers sound shrill. Lower brass sounds for cymbals are also overly emphasized (I've never heard the cymbal brush on the intro to Norah Jones' "Come Away With Me" sound so vivid). I have several plans to tame the treble peak:

Step one - Swap the current Crown PS-400 amp for the somewhat mellower sounding Emotiva Mini-X or XPA-200.
Step two - Swap the current Jolida tube DAC for the somewhat less romantic-sounding Emotiva XDA-1.
Step three - Use the "piece of paper towel or Kleenex over the tweeters" trick and see if the peak is attenuated
Step four - Switch from the "welding cable" wires to some braided wires that typically sound less vivid in the treble
Step five - If none of the above work, sell the speakers to some other old codger whose hearing is a bit farther gone than mine and who either won't hear the treble peak or else will think that it sounds really, really nifty.

Boomzilla

[PGT]

They're bipolar.....imaging is 3D not pinpoint. I used to sell those.....the 2004's are little ones.....8" or 10" subs I think. The big ones...BP2000's....they had a 15" driver. Put them on a 200x2 Adcom amp and put on some Def Leopard and THEY SCREAM!!! These are akin to a new generation of "house speakers", i.e. the big JBL's, Infinity's or Cerwin-Vega's. The marketing trick was the WAF.....they're tall slim towers that took up less floorspace because they put the big drivers on the side instead of the old monolith style cabinets that were wider than they were deep.

<----- made a lot of money sell BP2000's, BP2002's, BP2004's and BP2006's back in the 1990's.

[Boomzilla]

Any simple way to tame that treble peak?

[pdaddy]

Boom,
If you know anyone else who might want a newer model pair like this I have a new in box pair of Def Tech BP7006's.

emotivalounge.proboards.com/thread/32954/definitive-technology-bp7006-speakers-new

[PGT]

unplug or cover the rear tweeters would be a good start.

[Boomzilla]

I'm suspecting the rear tweeters aren't as big an issue for me as for most - I have a good set of sound absorber pads behind the speakers. Nevertheless, I'll try it.

Thanks - Boomzie

[PGT]

Found this....I believe all DefTech's used the same aluminum dome tweeters. Swapping to the Vifa's might be the ticket and they're not too pricey.

forum.blu-ray.com/showthread.php?t=213966

[RightinLA]

I like speakers with built-in powered subwoofers as long as their amps are working. I have a pair of Polk RTi100's (used as speaker stands as the subs aren't working), two pairs of theLSi25's and a pair of LSI Def. Tech BP7006's.
The Def. Techs are used for in an office with substantial space from the rear tweeter to the wall. Never noticed that they where overly bright. They are reasonably easy to drive and nice to listen to.
Congratulations on your newest find. Did you get them locally?

[bootman]

Boom, you really need to invest in a mic and measurement setup to really "see" what you are hearing.
I assume you are running these full range with no sub, correct?
My center has a built in sub and I like it crossed over at 80 vs full range.

[Boomzilla]

Hi all -

To answer the questions y'all have posed:

1. Yes, I'm running the speakers full-range with no external sub. DefTech (optimistically?) specs these built in subs to 17 Hz.
2. I found them locally on Craigslist for what I considered a reasonable price
3. I'm pretty sure that the speakers DO use aluminum-dome tweeters, but (at least so far) I don't think enough of the speakers to spend another penny upgrading.
4. I'll run the RTA iPhone app and see what pink noise looks like from the speakers - It isn't as accurate as a measuring microphone, but it should at least identify the peak frequency & amplitude

Although the bass from the built-in subs is impressive (and plainly DOES eliminate the need for an external sub), I've yet to "dial in" the imaging. I think I can deal with the treble peak without too much effort, but I may be wrong on that also. It's too early for me to say that I've gotten the best the speakers have to offer. Even if I don't get them to the point of being keepers as main stereo speakers, I think they might be useful as surrounds.

I'm out of town until after mid-week anyway, so I'll fiddle with the towers next weekend. Again - anybody with extensive bipolar experience is welcome to chime in on how to best place these speakers. The best I've done so far is with the speakers significantly closer together than average, with the speakers toed OUT slightly. This seems a really funny looking placement, but the sound is not at all bad. The center image has insufficient depth, but the image width is very, very good. Having the speakers toed out also reduces the treble peak somewhat. If I can get the treble peak abated, then other placement options become more feasible.

Cheers - Boomzilla

PS - The difficulty with the placement of these DefTech bi-polar speakers in my room seems to indicate that I'd have similar problems with di-polar speakers (specifically Magnepans) as well. Is this a fair conclusion? If so, then the Magnepans just fell off my bucket list. In fact, the experience with these speakers is also making me consider (again) whether the KEF LS50s might be the ideal speaker for me. I could run them with a small, high-quality sub and have what potentially would be the be-all, end-all of imaging. Thoughts?

[PGT]

equilateral triangle and a slight toe in is how I always set up BP's. You've got to pull them off the wall quite a bit as well. My first pair of "real" speakers were BP8's back in 1994 or so....bought them over B&W's actually (this was before the kevlar mid was introduced).

Spending $100 on four Vifa tweeters as a test is no-risk....15min of time and you can always return them.

[Boomzilla]

I guess that the main issue I have with bi and di polar speakers is that my room is asymmetrical. If you look at the first photo in the post, you'll see that behind the outside of the right speaker is an opening leading to my kitchen & laundry room (the big round white eye in the background is the clothes washer). Therefore, if I move the speakers outward and then toe them in, the rear radiation from the right loudspeaker (only) is lost through that door to another room. To say that this would foul up the imaging is an understatement.

For this reason, I'm about to conclude that the only way for me to get the best of these towers in my room would be to completely disconnect the rear drivers. Provided that the front and rear crossovers are in parallel rather than using any series elements, then this would work. If, on the other hand, the front and rear crossovers are used in series (or with any impedance-sensitive parts in common), then the speaker is destined, now and forever, to be a front and rear radiating speaker unless I want to redesign the crossover.

And yet, if I go to the trouble of sorting the crossover and doing away with the rear radiation, what do I have left? A mediocre two-way (with an annoying treble peak) in a tower with a self-powered sub. There's no guarantee that the speakers will image any better sans their rear radiation, and there's also no guarantee that even changing the drivers to better units will improve the sound sufficiently to justify keeping the speakers.

I may play with them some more to evaluate whether the speakers are worth any extra effort, but my gut feeling is that this wasn't a good choice to begin with. In a symmetrical room, these could be worth some effort. In a non-symmetrical room, I don't think they'll ever sound very good. Based on my experience with these to date, I'd say that these speakers were absolutely made for a very large, very dead (carpeted + absorbent furniture +absorbent or draped walls), and very symmetrical room. Used in such a room, the treble peak would be less prominent, the radiation would be identical from channel to channel, and the bass would have room to develop without peaks and dips. So do YOU have such a room? Hey, buddy, do I have some speakers for you!

It was worth the money I paid for the speakers to have learned about the peculiarities of rear-radiating speakers and how they behave in my specific room. It was also worth the money to know that henceforth I should avoid all bi and di polar speakers. This significantly narrows the choices in future speaker selection. I'm assuming that if midrange and treble will be asymmetrical in my room due to the openings in the walls, that it is fair to also assume that "full-range" speakers which radiate on the front only will also do poorly in my room. Why? Because the bass frequencies are essentially omni-directional (with or without rear ports). If the bass of the left speaker has room reinforcement, but the bass of the right speaker doesn't then the pair won't sound the same in my room. This argues (strongly) for a front-radiating stand mounted speaker crossed over as high as possible to a single, centrally located subwoofer. My Paradigm Studio 20s and my stand-mounted DefTech SM65s do well in my room because they don't have either low bass response or rear radiation. Presumably, this room asymmetry would also argue for a speaker with controlled directivity rather than the Revel / Paradigm / etc. proclivity for wide dispersion. This would narrow the "sweet spot" for listening, but that is OK with me.

I've made a large number of assumptions in the paragraphs above. Would those of you who know a bit more than I about speaker design chime in to confirm or refute these? Also, can youse guys recommend any stand mounted speakers with NO low bass that have NARROW dispersion?

Thanks - Boomhumbled

[yves]

www.enjoythemusic.com/magazine/bas/0508

[boog]

Boomzilla,

I have the exact same speakers with what sounds like a similarly asymmetrical room. If its any consolation I haven't been at all satisfied with mine for stereo listening either. You are spot on with the shrill treble, especially in female vocals, so much so that some recordings are too fatiguing to endure. I bought them new with home theater in mind which is really their strength. Great bass for effects and action. I replaced them with PSB Synchrony 1 towers (now gone) for 2 channel music. They were tremendous but too big an investment as it turned out.
Back to the 2004's, I like a deep soundstage and in my room this means pulling them out at least 5 feet from the front wall. No way with the WAF there so they sit about half that now. They are not doing it for me musically and I've fiddled with positioning ad nauseum. Home theater yes, music no IMHO.
Btw, Maggie and ls50's are one two on my to do list as well.
Good luck!
Hugh

[Boomzilla]

Hi Boog -

Great minds think alike.

[ocezam]

Oct 1, 2013 15:34:30 GMT -5 boog said:

I bought them new with home theater in mind which is really their strength. Great bass for effects and action.

Couldn't agree more. I've always felt Def Techs were great HT speakers. Wouldn't want to endure them in a stereo rig though.

[Deleted]

Sept 28, 2013 18:24:26 GMT -5 Boomzilla said:

Step five - If none of the above work, sell the speakers to some other old codger whose hearing is a bit farther gone than mine and who either won't hear the treble peak or else will think that it sounds really, really nifty.

Boomzilla

Step Five ..... Bingo!  OK, BZ, sorry but I'm going to be 100% honest here and not sugar coat my post, even though I'll probably be stepping on quite a few toes here.

First I'm not a fan of bipolar speakers.  I had the original Bose 901's in the early 70's and learned a life long lesson.  Any speakers that provide a significant amount of their sound by bouncing it off the wall behind the speakers usually have lots of issues with a natural sound except for perhaps for sources from a large venue like a symphony orchestra.  The off axis non-direct spread makes for far too dispersed solo vocals for example.  The idea sounds good on paper or as explained by a crafty sales person but fails in practice IMO.  I like the direct radiated sound as long as the highs are well dispersed by an excellent tweeter with wide dispersion for an ideal mix of direct and ambient soundstage (this is not always true with beaming tweeters).

Secondly, I am not fan of speakers with built-in subs.  It also sounds great on paper to many folks with the no sub(s) to irritate the wife.  That's where it ends for me.  As many of us know, the bass especially below 80Hz or so is greatly dependent on the location of the low bass producing speaker in the room.  Even with two built-in subs the lower bass sound is usually far from ideal.  For me keeping the subwoofer(s) separate in its own adequately large enclosure, which can be moved as needed, is essential for the best performance.  The BP towers usually are only ideal in one location.  Of course more than one separate sub can many times be even better.  Built-in subs or smaller sized cube style subs might keep the enclosure size of the speakers in the room to a minimum  and please the boss, but they do not offer the best in low bass performance.

The few review graphs I have seen on the Def Tech bipolars seem to indicate a tweeter response that is peaked at about the 10kHz area, again bingo!  You don't show your pre-pro, but one like the Emo UMC-200 with the 11 band para-EQ should allow you to tame the irritating peak that you are hearing. A frequency response test at your listening seat should confirm if this is the issue.  The graph below is from a review of the BP-8080ST in S&V Magazine. It has two 1" aluminum tweeters that I believe are the same or similar in FR to the BP-2004.

I hope I haven't stepped on too many toes, just my honest opinion.   




 

[Boomzilla]

You NEVER step on my toes, Chuckie. I haven't disagreed with you yet, but if I did, I'd still listen very, very carefully to your opinion - you know audio!

Yes, every issue you mention is so. If (ah say, IF) I didn't already have much better speakers on hand, I might try a bit of EQ to improve these DefTechs. Since I have not one, not two, but three better pairs of speakers in the house, these are Craigslist bound. For someone into HT, these could be fine; for someone into music, not so much.

I've got a pair of Magnepan 1.6s on the way soon. I doubt that they'll do much better than the DefTechs, but I'd never be satisfied until I at least tried them. Therefore, one more "bucket list" item down.

By the bye, Chuckie, can you recommend me an inexpensive analog preamp with some basic tone controls? I'm waiting for Emotiva's tube preamp to come out, but would like to try some slight contouring of a couple of my existing speakers. I tried the 1/3 band DBX pro equalizer, but it was a bit much. I need some attenuation when I use my XPA-2 and I'd rather not introduce the variables that a passive volume control creates.

Thanks - Boomzilla

[bootman]

Oct 2, 2013 14:39:02 GMT -5 Boomzilla said:

I've got a pair of Magnepan 1.6s on the way soon.

I think you will be pleasantly surprised. (what amplification are you going to use?)
Just sayin.

But please do post your thoughts in a separate thread.

[Boomzilla]

Well, they aint here yet... If the deal goes through, maybe in a week or two. I've got an XPA-2 just waiting to jump, and I also have a pair of Crown PS-400s for biamping. Front end duties to be done by either the Jolida tube DAC or a Stealth DAC. Sub (not at first, but maybe eventually) will be the B&W ASW-675.

Having the DefTech Bi-Polars in the house has been helpful in finding the (one) place where rear radiation works in my room. The speakers will have to be too close together, but they'll have semi-identical back wave conditions.

Just as an aside, I understand the mechanics and differences between bi & di polars, but how will the sound differ (assuming, for the moment, that I could switch the SAME pair of speakers between di & bi polar modes)?