[Telstar]

Yet Another Open Baffle

My latest idea is based on the excellent MJAO Anagram by scorpion.

Goals: 3-way, easy to drive, active bass, low-cost, decent WAF, active bass and of course very good sounding

Woofers: 2x Eminence Alpha 15A (15", 8 ohm, Fs=42hz) OR 2x Peerless SLS-325 (12,5" 8ohm, Fs=)
Smaller drivers would allow a narrower baffle, which is a big + in the WAF department

Midrange: 2x Monacor MSH-115 (4", 8 ohm), in series (MTM config). Considering also the MS-100CHQ. but i would make the precious midrange as easy to drive as possible, so the 115 would be my first choice.

Tweeter: 1x Monacor DT-28N (8 ohm)

Baffle: 35cm (40cm if the Alphas are used) x 120cm, tweeter centered at 93cm. Flat or rounded top.
Wings: Thinking about a U frame, open box for one woofer (à la lampizator), or sloped wings. Suggestions welcome. I would like to go down to 30hz. Alternative woofers are the AE OB15 and the Hawthorne Augies, but prices are about double for either, considering shipping and customs.

The crossover for the passive parts (mid and tweeter) would be based on the MJAO, using 40uf for the mids.

The drivers will all be centered, except maybe the tweeters.

The BOM accounts for about 550 euros, including everything but the plate amps.

Any comment or suggestion welcome.

[scorpion]

Telstar,

You seem to be looking both here and there for alternatives. 

However regarding YOP3.

You can just be copying the MJAO and bi-amp. Keep the filter, I think your F3 would handle the mid and high units.
A plate amp for subwoofer use would probably not do because it will cut the bass at too low frequency. Any decent SS amp would do fine.

Two simulations, the first is 2 Peerless SLS + one MSH115 on a baffle exactly like the MJAO-baffle. That would give you a Mid - High impedance of 8 ohm. LP for the bass is set to 300 Hz with Linkwitz-Riley 12 dB/octave filter and HP at 400 Hz with the same charateristics. You might have to experiment a bit with the crossover frequency for DT-28N depending how MSH-115 behaves in comparison to MS-100CHQ.



Next simu is for 2 SLS12 (in parallel) + 2 MSH-115 (in parallel) on a baffle mesuring 42" x 14" where the tweeter sits centered at 37" and mid-units just below and above it as you state above. The same crossover frequencies and tweeter reservation applies, but now mid will be 4 ohm and tweeter 8 ohm.



and when the bass is boosted 8 dB:



The SLS will be responding very well down to 40 Hz, a bit to my surprise with this baffle-width, and they certainly are good bass-units.
I am a little surprised over 'fivestring's measured response curve. But as he has not disclosed any technical details about his nice looking baffles, I suppose he bi-amps and also bass-EQ a bit otherwise 40 Hz response would have been lower and not higher than what's measured at 100 Hz. 

/Erling

[Telstar]

Telstar,

You seem to be looking both here and there for alternatives. 

Yes, I know.
I cant set my mind yet onto something and stick to it (and also for the fact that i cant do simulations myself). I maybe could if I had a 6 times bigger budget.

Thanks for your time. I'll be following your project and if I realize the YAOP3, I'll sure let you know.

[Telstar]

The SLS will be responding very well down to 40 Hz, a bit to my surprise with this baffle-width, and they certainly are good bass-units.

Do you think that with a 20hz bass boost from the plate amp (or the T-bass circuit from diyaudio), I can get to -6db at 30-32hz?

I am a little surprised over 'fivestring's measured response curve. But as he has not disclosed any technical details about his nice looking baffles, I suppose he bi-amps and also bass-EQ a bit otherwise 40 Hz response would have been lower and not higher than what's measured at 100 Hz. 

I'm going to ask him

[scorpion]

I you go with 35 cm wide baffles then 32 watts in the 4 ohm load of two parallel SLS315 will get you - 3 dB at 40 Hz and - 6 dB at 30 Hz within SLS 315 Xmax referenced to 100 dB at 70 Hz.

/Erling

[Telstar]

I you go with 35 cm wide baffles then 32 watts in the 4 ohm load of two parallel SLS315 will get you - 3 dB at 40 Hz and - 6 dB at 30 Hz within SLS 315 Xmax referenced to 100 dB at 70 Hz.

/Erling

Thanks!
So I can go with the smallest of the Alesis amps:
http://www.alesis.com/ra150
I heard those used to power a Linkwitz Orions and the bass was very convincing.

For xo, low freq boost and eventually a damp in the 60-80hz range, i'm thinking to get this:
http://www.reckhorn.com/index.php?ln=en&prod=b1
or this:
http://www.reckhorn.com/index.php?ln=en&prod=s1

[scorpion]

Guido,

Which speaker units are you considering ?

/Erling

[Telstar]

Guido,

Which speaker units are you considering ?

/Erling

For the bass a pair of Peerless SLS-315 each speaker, crossed and amplified as per my previous post.

For the rest, I haven't decided between a fullranger and mid+tweeter.

The first option would likely see a Supravox bicone.
The second option could have a driver such as the Tone Tubby 12" for midrange in alternative to the Monacor. I have got a very good price offer for that.

[scorpion]

You know the Reckhorn units are subwoofer (1 bass channel) x-overs. Before you have decided on top-units you cannot see where to put x-over frequency.
You may also have to boost lowest mid to get an even response. Lots to think about !

/Erling

[Telstar]

You know the Reckhorn units are subwoofer (1 bass channel) x-overs. Before you have decided on top-units you cannot see where to put x-over frequency.

They have variable XO up to 300hz. The difference of the two models is basically the addition of a variable dip in the S1 model, which I think it can be useful between 60 and 100hz due to my room modes.

But you are right that i have to start on the top. That's what I'll do. I want to measure the lowest response of the mid/tw.

You may also have to boost lowest mid to get an even response. Lots to think about !

I'll never do this, it can eat the dynamic headroom of my F3. If I have to, I'll raise the XO point of the bass.