Integrating tweeters with b200 - preserving efficiency

mcgsxr · « **on:** 21 Apr 2009, 07:25 pm »

This might prove a non starter, but I want to get a few opinions.

I have been using OB Visaton b200's for 4 years now, and have the Planet10 phase plugs etc. I know I am still missing treble. I don't need dipole tweeters, I can live with monopole treble from 5K or 10K on up.

I am considering finding a way to integrate tweeters (ribbons would be cool), but cannot lose efficiency - my 3-5wpc Magnavox amp, using the 1v input from the Bolder SB3 is often already at 70-95 of 100 volume steps.

I have read opinions on how effective (or not) just adding a tweeter with an Xover to the tweeter would be.

I expect to continue to use OB subs, though new baffle designs are having me consider TL bass too, using the drivers I currently have, and continuing to biamp with the BASH amp for the subs.

Thoughts?

mightym · « **Reply #1 on:** 22 Apr 2009, 01:09 am »

At the risk of being crucified by others, have you considered using a high eff dome? Lanzar ( yes I know they're CAR speakers ) has a supposed very smooth and 96 Db eff. silk dome tweeter. I wish I could recall the model #.

A few minutes of searching should rectify that.

John

Edit: Lanzar DCT, and TWS are both 96Db, DCT is silk,and TWS is Titanium. You could always go with a bullet horn, they are very efficient.

I found the above while looking for a small efficient tweeter to mount co-axially with an Eminence 12lta.

mcgsxr · « **Reply #2 on:** 22 Apr 2009, 01:14 am »

I won't hold a car speaker suggestion against you, I happen to have more respect than most for quality car audio. I run Zapco 6.5 components in my Accord, and have an old school Orion amp.

I have considered car audio tweeters, I will have to scope out a set of those Lanzar's, and gaze at their specs etc.

Thanks for the idea.

Now, the integration portion will still be a challenge.

mcgsxr · « **Reply #3 on:** 22 Apr 2009, 01:18 am »

http://cgi.ebay.ca/NEW-LANZAR-1-200w-SURFACE-ANGLE-MOUNT-CAR-AUDIO-TWEETER_W0QQitemZ200332322869QQcmdZViewItemQQptZCar_Speakers?hash=item200332322869&_trksid=p3286.c0.m14&_trkparms=72%3A1215%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

These the ones you mean? 96db efficient apparently.

ebag4 · « **Reply #4 on:** 22 Apr 2009, 01:35 am »

This is a link to the silk dome Lanzars (96 dB), don't know if they are the same units mightym was talking about:

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?Source=googlebase&ProductID=12889

Best,
Ed

mightym · « **Reply #5 on:** 22 Apr 2009, 01:40 am »

Ed, those are the ones, but AWE has em for $12.95

www.audio-warehouse.com/web/mdl/DCT/detail.asp

John

I edited my first post while you guys were posting.

markC · « **Reply #6 on:** 22 Apr 2009, 01:45 am »

How about these from Danny. http://www.gr-research.com/index.asp?PageAction=VIEWPROD&ProdID=109

mightym · « **Reply #7 on:** 22 Apr 2009, 01:54 am »

I forgot abut those, Mark. reasonable price too. My original thinking re: integration was to make a bracket to mount the Lanzars in front of the Visaton, like a co-axial. A little bit of Aluminium bar stock, and some hardware and a couple pieces of CAT 5 to wire it....paint it black....

Just a thought.

John

markC · « **Reply #8 on:** 22 Apr 2009, 02:33 am »

I thought about that exact same construction. Then I decided to make the x-over point much lower and just mount the tweet as close as possible to the B200.

mcgsxr · « **Reply #9 on:** 22 Apr 2009, 02:03 pm »

Thanks for the ideas guys, looks like I have at least 2 choices for tweeters that will affordably cover off meeting the efficiency requirement.

Building the Lanzar over the b200 as a coax of sorts is interesting - would I still have issues with the b200 run full range, and the tweeter coming in around 5 or 10K - combing issues?

I know that MarkC's solution is a good one, though I lack the 300wpc he has, to make up for the efficiency loss due to Xover, and smoothing circuit etc.

I have the phase plugs in my b200's, so I could actually consider mounting a short column in place of those, and mount a Lanzar to that...

Telstar · « **Reply #10 on:** 22 Apr 2009, 02:35 pm »

The Morel CAT 378 is 93db eff, with a little waveguide looks perfect for OB and it's affordable at around 60€:

http://www.morelhifi.com/products/pdf/Tweeters/CAT/Specs%20sheet%20CAT378.pdf

Rudolf · « **Reply #11 on:** 22 Apr 2009, 05:06 pm »

Quote from: mcgsxr on 21 Apr 2009, 07:25 pm

I don't need dipole tweeters, I can live with monopole treble from 5K or 10K on up.

Thoughts?

I question both proposals.
First the crossover frequency: At 5 kHz the difference between on-axis and 45° response of the B200 is about 12 dB, between 6-8 kHz it´s 15-20dB. If you want to avoid a big change in the radiation pattern at the crossover, you need to lower that point to 3 kHz max. 2 kHz would be preferable.

I´m fully convinced that the ongoing uneasiness with the B200 treble stems from the gross difference between on-axis and off-axis SPL in that area. Following the dipole pattern of the midrange with a dipole pattern for the treble has convinced almost everybody who has tried it - although not with the B200 AFAIK.
The Dayton ND20Fs are cheap enough to give it a try - with an efficiency that suits the B200 treble very well. Their marginal depth would allow to mount them back-to-back even on a 1" baffle. From 2.5 kHz up their distortion level is less than the level of the B200 itself.

For sure there are much better tweeters (like the Visaton SC 4 ND), but at the price of the Daytons you can satisfy your curiosity for cheap before investing in the real thing.

Rudolf

mcgsxr · « **Reply #12 on:** 22 Apr 2009, 07:21 pm »

Interesting points Rudolf, and I will have to think about it.

Just to be clear, you realize I am thinking of continuing to run the b200 full range, and bring in a tweeter at 5K or 10K right?

I will review your points, and add them to my considerations.

Thanks,

Rudolf · « **Reply #13 on:** 22 Apr 2009, 08:07 pm »

Mark,

this is a set of off-axis measurements for the B200 in infinite baffle:

and this is the corresponding CSD:

What I see from both: The B200 doesn´t have a major problem above 10 kHz. From 5-10 kHz the polar response is not optimal, but at least quite constant. The CSD is improving in that range.

The real mess is in the 1-5 kHz region: rapidly changing directivity and heavy resonances. So where is the point in "improving" the 5 kHz and up range and let the real problem area stay untouched?

It is evident that an additional sound source can be considered only above 5 kHz. Any tweeter starting significantly below 5 kHz would need the B200 to be attenuated correspondingly. So if you insist on running the B200 full range, it would be consequent to bring in the tweeter at 5K or 10K only, yes.

Rudolf

BrassEar · « **Reply #14 on:** 22 Apr 2009, 10:28 pm »

Unless you are younger than 30, I would wager that you have very limited hearing over 10 KHz. Anyone over 30 (especially male) that says they hear in the 15-20 kHz range is deluding themselves. Get a competent hearing test and prepare to be shocked. My hearing taps out at 10 KHz.

As far as tweeters in general - compression drivers rule both in efficiency and dynamics. Domes are toys after you have played with the big boys. aa

richidoo · « **Reply #15 on:** 23 Apr 2009, 12:01 am »

Why not active amp the tweeter like you are doing with your bass driver? Solves the efficiency issue. Put a low level crossover before the amp. A car chip amp is all you'll need to match the array's high efficiency. TDA7560 is very easy to use, 4 channels of 10W.

Telstar · « **Reply #16 on:** 23 Apr 2009, 09:51 am »

Quote from: BrassEar on 22 Apr 2009, 10:28 pm

Unless you are younger than 30, I would wager that you have very limited hearing over 10 KHz. Anyone over 30 (especially male) that says they hear in the 15-20 kHz range is deluding themselves. Get a competent hearing test and prepare to be shocked. My hearing taps out at 10 KHz.

I'm male, over 30 (but not by much) and I can hear to 17k, maybe more - it probably was the headphone rolloff.
Not only, but my ears are very sensitive to HF distortions, that others seem to not notice.

Besides, i believe that a supertweeter can be helpful to create ambience, even if not decoded by the ears.

Sjef · « **Reply #17 on:** 13 Oct 2009, 09:52 pm »

why not try a supertweeter "on top" of your baffles.
I have been experimenting alot with fullrangers and supertweeters and from my experience I can tell it always sounded better with the suppertweeter in 'free air', not mounted on the baffle. I also found it sounded better when the distance between the fullrange driver and the supertweeter was in the range of 10 to 20cm frame to frame, quite in contrast of what the frequency lobing theory discribes. In fact I measure much less lobing effect this way. Everyone seems to be obsessed by this one theorie that they forget a lot of the other aspects in loudspeaker design. Just try it, it's pretty easy.

I have never had a b200 but a lot of other 8" drivers. From your picture I see that the b200 is mounted pretty low. Most 8" drivers sound realy a lot better at ear height, makes them a totally different loudspeaker. With all the 8" drivers I always ended up with a +/- 3500Hz crossover as best sounding, when the driver are close together and around 8 to 10 kHz with the drivers 15 to 20 cm apart. again, this can't according to the frequency lobing theorie, beats me

THWO · « **Reply #18 on:** 21 Oct 2009, 03:59 pm »

Hi Mark

how about considering the really compact 8 ohm horn tweeter "img Stage Line MHD 220 N / RD" ? Nice to use at not below 5000 Hz, enjoys 104 dB - may be something worth having a look at. You may have a look at it at http://www.monacor.de/typo3/index.php?id=58&L=0&act=8&act_sub=24&artid=6429&spr=DE&typ=u (sorry, all in German, but my be the datas help a bit).

I use it as support for the Ciare CH250 in open baffle and it works well.

Regards,
Till

Rudolf · « **Reply #19 on:** 21 Oct 2009, 09:21 pm »

Hi Till,

they've got the description for the MHD 220 N / RD in English too:
http://www.monacor.de/typo3/index.php?id=58&L=1&spr=EN&artid=6429&typ=u&hkatid=&ukatid=&brand=
Look for the flags in the upper right corner of the Monacor homepage

Rudolf