What do people think about this open baffle speaker?

[Melon Head]

What do you guys think about cloning this speaker?
6moons audio reviews: Yamamoto SoundCraft YS-500

[fmena]

it seems that it only goes to 18K, so maybe a super tweeter would be nice to add? It kind of reminds me of 4 Pi Speakers from the USA (Pi Speakers - unmatched quality and state-of-the-art performance) in that it they also use Eminence and B&C components in their designs, but Yamamoto has an open baffle configuration instead.

FM

[Melon Head]

Specifically, I was wondering what people think about using the low QTS deltalite woofer in an open baffle arrangement I know Troels Gravesen also uses this woofer and prefers it over Eminence Alpha. Most people recommend QTS around 0.7 but the deltalite has QTS=0.38

What is necessary to effectively use low QTS woofers in open baffle speakers?

[a.wayne]

I guess some do get bored ....

[ScottG]

Originally Posted by Melon Head

What is necessary to effectively use low QTS woofers in open baffle speakers?

1. *Large* baffle, or
2. Heavy resistance to lower motor strength and raise Qe, or
3. Equilization in the filter, either actively or passively.. or an eq. before the filter, or
4. Transition to another source (or sources) of pressure to sum flat. (..like an active sub used as a woofer with a broad and "shallow" low pass filter).

..usually a combination of 1, 3, and 4.

[Melon Head]

Can anyone show a modelled frequency response of two woofers QTS=0.38 vs QTS=0.7-1.0 on a baffle width of about 20" with wings of acceptable depth.

[c2cthomas]

Couldn't you just leave the back off of an EconoWave?

Well - I would need to find a price for "an Ebony-encased polypropylene capacitor sourced from the American Dearborn Co." I'm betting that it isn't cheap........ Hmmmmmmm............... does PE have a suitable sub for that cap???

BTW - I like the speaker!!! It takes me back to the days of an old stereo console my parents owned back in the mid '60's. It had a stereo tube powered amplifier - probably about 25 watts per (maybe less) a record "changer" which had a huge plastic arm and most likely tracked at around 1000 grams
and an AM/FM radio. I think it might have been a 3 way system with 12 inch woofers - 3 or 4 inch mid's and I don't know if it even had tweeters!! The back was open - and it sounded as sweet as the big 'ol juke-box down at the soda fountain.

The attached photo is off of the 'net - and not an actual photo of our old stereo - but you get the idea......

[Pano]

Originally Posted by Melon Head

What is necessary to effectively use low QTS woofers in open baffle speakers?

Usually a very large inductor. Anywhere from 12 to 20mH. This fights the rising response of the low Qts woofer on an open baffle. It can work quite well. Trade off is loss of efficiency.

Active EQ can do the same thing, but you still lose efficiency.

[Melon Head]

Thanks
I would love to see a frequency plot before equalising.
How much efficiency is lost through passive equalising?
If it is no more than 6dB than I might be in business.

[Pano]

It can be 10dB depending on baffle size, Qts and other things. There is no free lunch.