Repurposing Bose 901's For Line Array PA

[LiquidStudio]

Howdy,

I'm new here. This is my very first post.

I have a band, a pair of Bose Series II 901 speakers with the EQ and an AB International 400A amplifier AB International Amps - Amplifiers.
The PA would handle mostly vocals and plugged-in acoustic guitar. There may be a little overhead on the drumkit mixed in, but no electric guitar or bass guitar.

Would it make any sense to rip apart the old 901's and re-use them in two Line Arrays with 9 drivers each (plus a HF driver or two maybe) for a 4-piece band playing smallish venues like pubs and patios?

Thanks,

Norm

[Loudthud]

A close friend of mine had a pair of 801s and a pair he built driven by a Crown DC300 (300 Watts per channel at 4 ohms) in the 80s. They always sounded very clear especially when mounted on stands where they projected well to the crowd. Fine for small venues, neighborhood bars and restaurants. Put them up against my pair of biamped Altec A7s (less than 300W total) one time and they were 6 to 10 dB lower in volume even at twice the power.

[bear]

Imo, the vertical array thing is a good way to go, up to a point.

There is a nice thread on the curved array, by Keele (iirc) here on DIY, you should read the original paper, it tells an interesting story regarding the vertical dispersion.

But given the 901's extreme EQ, they're not a good choice for PA use. I'd suggest making a purpose built line array for PA use - different drivers. You'd not want to run them into low bass, generally speaking.

My thinking is to use high output drivers, at least in the mid 90's SPL, then running them in series parallel, you'll get up around 100dB/1w/1m, and with the line array configuration they will tend to have good audibility at modest distances... given that your gigs are like that, it is a good choice imo. My suggestion is to find the best sounding compression driver + horn config for the highs, keep in mind that they will not disperse like a simple line array... or you can maybe find a ton of super cheap tweeters and make a paralleled HF array... so you have to use more than one horn on top, or use some means of creating wider horizontal dispersion (you do not need much vertical dispersion...

_-_-bear

[LiquidStudio]

Originally Posted by Loudthud

A close friend of mine had a pair of 801s and a pair he built driven by a Crown DC300 (300 Watts per channel at 4 ohms) in the 80s. They always sounded very clear especially when mounted on stands where they projected well to the crowd. Fine for small venues, neighborhood bars and restaurants. Put them up against my pair of biamped Altec A7s (less than 300W total) one time and they were 6 to 10 dB lower in volume even at twice the power.

I guess I need to set the band up with the 901's as they are to see how they work be fore I try to gigi with them. I thought there might be some advantage to re-configuring them into line arrays.

[Zero Cool]

Low efficiency, too wide of a vertical dispersion for line array use, low power handling, absulutly NOT a good choice!

[Keriwena]

I don't have any experience with the Series II's, but when I was selling the original 901s I got a phone call from Amar asking me to stop turning them around when demoing with rock music. Our point was, when you did that, they sounded more like a PA system than Symphony Hall, so they sounded more like what you heard at a rock concert.

Funny thing - shortly after that, the 800s were introduced.

[cyclecamper]

Well, I used to have 8 pairs of the Bose pro PA speakers, basically the same thing without the 9th driver and with a balanced input on the active equalizer (and there's two resistive bass reflex ports in a desperate attempt to get more efficiency).

I'd imagine one single-driver column of those little drivers might have enough output for my bathroom but not enough low bass.

IMHO it requires at least 64 of the Bose drivers to even consider it a real PA, and then you also need a real sub, as even the later Bose offerings have. 128 drivers starts to sound OK for medium size rooms. But the Bose PA speakers DO have a passive crossover inside, in addition to the active EQ. The early ones had one horizontal row of 4 dirvers full-band and the other horizontal row was thru a low-pass. That caused problems when stacked. So the next generation had the two center columns full-range and the 2 outer columns thru the passive low-pass filter, which worked better when stacked.

To tell the truth, I liked the Bose but the foam surrounds on the particular generation of driver I had was a real problem. Imagine refoaming hundreds of little driver surrounds...I dumped the junk before I finished.

If you want to use a lot of little drivers, it would be interesting to make a PA with sealed boxes more like the original Bose concept.

But the rear-firing speaker was probably a mistake for stereo IMHO, just confusing the soundstage with lots of early reflections.