Do Bose 901 series 1 speakers have crossovers?
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Audioraven
Well-Known Member
Bose 901's do not use crossovers. All 9 drivers receive the EQ'ed full range signal together.
As Audioraven indicates, there is no crossover Haydn in the Series 1.
In have a pair, and I strongly suggest considering a recap of the EQ, as the electrolytic caps used in the EQ have likely drifted way out of spec.
Recapping the unit will bring it Bach into spec.
In have a pair, and I strongly suggest considering a recap of the EQ, as the electrolytic caps used in the EQ have likely drifted way out of spec.
Recapping the unit will bring it Bach into spec.
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spkrdtr
spkrfixer
Aaaah, a classical music lover no doubt! :thmbsp:
DavidR623
Active Member
None of the 901 series speakers use crossovers. They incorporate nine full range drivers and need the series appropriate Active Equalizer to enable the drivers to produce highs and lows.
As already mentioned a Series I EQ will need a recap of the capacitors and perhaps other components to bring it back into or better than original specs.
As already mentioned a Series I EQ will need a recap of the capacitors and perhaps other components to bring it back into or better than original specs.
Just following the OP's lead.
"Are the Bose 901 series 1 crossovers internal to the speakers or does the equalizer Handel the frequency separation for the speakers?"
Anyway, he now knows there is no crossover. I hope he doesn't go Chopin them up looking for one.
Copa1934
My ears are bleeding
You two are funny. I didn't pick up on "Handel". Too funny.
Hey, I own first Gen (aka Series I) and currently use the Series II EQ. Had two of the first Gen EQ's but the II sounds better. So you can either go I/II, but I agree doing a recap is a very good idea.
But, more importantly don't run them without the correct EQ. You won't be very happy, you can almost count on this. Almost? There are some owners who have indicated they are quite happy without the EQ. So it does very.
kaplang
Works for me !
I was considering a recap but decided not too. After removing the power supply filter caps and testing and randomly removing and testing some of the other caps they all tested within at at least 10% of their value. Some were within 5%. I may recap later on down the road but right now I don't see the need. It seems to be doing a great job at controlling my 901s with all of the original capacitors.
They must've built mine with a bad batch of caps. Many tested >50% off, some high, some low.
I agree no need to replace if they are within spec.
Pio1980
AK Member
No crossover, but a rather drastic equalizer which could be argued was worse.
Sent from my SM-N900V using Tapatalk
Copa1934
My ears are bleeding
Really? No different, say, from a manufacturer that decides to make their amp "warmer" or "brighter" or some other variation. Without all those makers with different ideas of how the signal from an LP, CD, Tape or other medium should be produced/processed, we'd all effectively be listening to the same thing.
However, mucking with an already "amplified" signal, that's not only a horrific challenge, as anyone who has built speakers can attest to, but a far less forgiving art.
Bose, at least, was working with one set of drivers and adjusting a signal accordingly. With the exception of other single driver systems, everyone else tries to make totally different drivers behave and act in concert with each other, all the while each working with different frequencies, having different sonic qualities entirely, having different efficiency, impedance, impedance curves, and on and on.
Bose made the right call. That others don't agree is there opinion. I own many styles of speakers, bass reflex, acoustic suspension, transmission line, cone, ribbon, leaf, paper, poly, various metal compositions, and more. The Bose 901 is easily in my top 5 speakers, that I personally own.
I don't understand why this comes up, comparing networks to active EQ. It's a silly argument since it's two similar methods of making speakers do something they weren't intended to do. Don't think so? Try ripping out the networks to your beloved speakers and report to us how they sounds sans networks. I'll be waiting for that write up.
Crossover approach: hey, this driver doesn't do so well above frequency x and below frequency y, so let's add electronics so that it doesn't have to cover those ranges, then add other drivers to take over those frequencies.
Equalizer approach: hey, this driver doesn't do so well above frequency x and below frequency y, so let's add electronics to force it to do it anyway!
Sounds goofy, but given the number of 901s sold (and not an inexpensive speaker, either) it seems valid, also.
Equalizer approach: hey, this driver doesn't do so well above frequency x and below frequency y, so let's add electronics to force it to do it anyway!
Sounds goofy, but given the number of 901s sold (and not an inexpensive speaker, either) it seems valid, also.
Pio1980
AK Member
It come up because of relative degree of signal path clutter and phase shifting thru either, leaving out the controversial direct/reflected theory of reproduction of the 901.
Some good 2-way designs only had one capacitor as the crossover (Epicure/EPI ?).
Sent from my SM-N900V using Tapatalk
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So Wagner you gonna get this project done? Vee are vaiting!
Copa1934
My ears are bleeding
Stop, stop, you guys are killing me.
Tom Bombadil
AK Member
A friend of mine was once employed by Bose to test drivers. They were shipped in by the truckload. Said he saw an invoice which stated that the 901 drivers cost $4 each. This was back in the 90s. The testing procedure was to test the output at 4 frequencies. As long as it measured to within + or - 6dB of the desired output level, it passed. He asked someone about why the criteria was so forgiving and was told that once they were in a box with 9 drivers and driven through the EQ, it really didn't make much difference unless they were far out of spec.
Copa1934
My ears are bleeding
Personally, I'd consider 6db pretty bloody tight given the output at 1w is roughly 80db+ (closer to 90 based on my personal measurements).
Today, however, we have so much better measuring equipment. I've used DATS to identify things I could NEVER hear with my ears. Impedance curves, min and max frequencies. How stable the impedance/frequency curves. Back then you likely would have to know how to operate a scope to get the info we get from DATS software. And far more time consuming, back then.
Any speaker will have inflated prices, there's no getting around that. The same "equivalent" drivers went into Polk speakers. Polk likely paid a similar price as they sourced them from CTS, but this was back before Bose built their own drivers, or had them built to tighter standards. Polk later, I'm sure, would go with yet better speakers.
An equivalent (very close I might add) raw driver was sold by RS for roughly $10. If you bought in the thousands that price would likely drop to $4 or $5ea. That driver, by the way was a Fostex 103. They also carried another driver, 5", for around $17ea.
