I am the original owner of a B&W 802F Series 1 with the sealed woofers cabinet with the Fibrecrete heads. They are sitting there and I don't know what to do with them.
I am thinking of converting this into an active system using the MiniDSP Flex. I don't have high decibel needs and feel the 4 8" woofers can get me down to the last octave. My thought is that it would cost me more to create something similar than simply repurposing it. I have the amps necessary already.
https://www.minidsp.com/products/mi...Gvi4Gfh7ngP9pwaeiEi7jpIuTh-P-Qb4aAl9bEALw_wcB
Any ideas why this should not be done? Or why it might be a good idea.
I am thinking of converting this into an active system using the MiniDSP Flex. I don't have high decibel needs and feel the 4 8" woofers can get me down to the last octave. My thought is that it would cost me more to create something similar than simply repurposing it. I have the amps necessary already.
https://www.minidsp.com/products/mi...Gvi4Gfh7ngP9pwaeiEi7jpIuTh-P-Qb4aAl9bEALw_wcB
Any ideas why this should not be done? Or why it might be a good idea.
I am thinking of simply using a modern DSP active with phase and more filtering. The series 1 filter seems to be a 24db per octave type. To control low frequency excursion B&W actually put is a large electrolytic cap in series with the woofers. It is now over 40 years since I have had these and now understand why they always wanted to played loud...and many commented about anemic bass. They truly are studio monitors and were meant to be played loud. Today I am planning to downsize yet experiment with interesting equipment. DIY with a good finish are out of the question for me. So these old speakers could provide a decent platform to play with using the Minidsp flex and voice the speakers the way I like them to sound at a level I am comfortable with.
They would be a good learning experience. While they do 24dB/octave, this doesn't mean you can ignore the response variations of the speaker. If response and phase looks good with the filters it can still be incorrect at the speaker.
This is to increase the bass extension with a third order rolloff.
Arrgh, just realized the Flex is only a 4 output design. Those 6 jacks fooled me.
Moving to DSP with more channels gets more expensive very quickly.
Moving to DSP with more channels gets more expensive very quickly.
Before you start, decide how you want to measure. 3-way set up by ear is a very bad idea,
You should measure them as they are, any chassis for its own and combined, including the passive x-over. Document exactly where the speaker and microfone where placed during measurments. This way, to some degree, you can compensate for the room you measure in. If the nearfield measurement of a chassis is identical, passive and active, it will radiate the same in other directions too. So you can save yourself hundrets of directional measurements.
If you then correct the phase between chassis in the DSP, you will have a basically correct response to the passive speaker. Keep one speaker stock, so you can compare A/B to the baseline!
Anyway, the sound should improve drastically by the removal of passive parts in the construction and the direct connection of dedicated amps.
Taking such a systematic approach will take a lot of guesswork out of such an activation.
If you have such a starting point for the activated speakers, which basically is a copy of the passive response, you can later improve to personal taste, room response and interior by tweaking the DSP.
The capacitor for the woofers is a very delicate task, maybe bridge the cap, so you realize how much it improves the bass response. It seems you think the cap is a bad thing. This is not the case, it is part of a clever construction and you can NOT replicate its function in the DSP, as many might think.
You will soon realize this is much more than connecting a few wires...
You should measure them as they are, any chassis for its own and combined, including the passive x-over. Document exactly where the speaker and microfone where placed during measurments. This way, to some degree, you can compensate for the room you measure in. If the nearfield measurement of a chassis is identical, passive and active, it will radiate the same in other directions too. So you can save yourself hundrets of directional measurements.
If you then correct the phase between chassis in the DSP, you will have a basically correct response to the passive speaker. Keep one speaker stock, so you can compare A/B to the baseline!
Anyway, the sound should improve drastically by the removal of passive parts in the construction and the direct connection of dedicated amps.
Taking such a systematic approach will take a lot of guesswork out of such an activation.
If you have such a starting point for the activated speakers, which basically is a copy of the passive response, you can later improve to personal taste, room response and interior by tweaking the DSP.
The capacitor for the woofers is a very delicate task, maybe bridge the cap, so you realize how much it improves the bass response. It seems you think the cap is a bad thing. This is not the case, it is part of a clever construction and you can NOT replicate its function in the DSP, as many might think.
You will soon realize this is much more than connecting a few wires...
PS for a start you could use a Dayton Audio DSP-408 or two Mini DSP. All the features of the mini DSP FLEX do not really help you with the conversion of your speakers. Don't fall for all the promises the sales department makes.
The sonic differences of DAC's and DSP's are much lower than you may think if you follow such sound discussions. In the end they are reduced to the differences you hear from two different CD-players.
These low cost DSP have a very good resale price, so the risk you take is minor.
The sonic differences of DAC's and DSP's are much lower than you may think if you follow such sound discussions. In the end they are reduced to the differences you hear from two different CD-players.
These low cost DSP have a very good resale price, so the risk you take is minor.
Acquired a MiniDSP Flex 8. Looking at the original schematic of the 802 F versus later versions the crossover of the original appears to be a electrical fourth order. Newer versions appear to combine the acoustical and electrical for a combined response. In any case, my going with the old speakers is to utlize the cabinets and physical aspects. I don't have a workshop but this platform will provide hundreds of hours of tinkering and measuring without the burden of fabrication and finish. Also I will retain all aspects to return to original if it is needed. No no major cutting etc. I will simply elevate the speakers a few or couple inches and lead the wires out. I will be busy for another year or so!
Try and have a word with Serge Auckland who posts on hifi wigwam he Activated a pair of 801f speakers a while ago and they use exactly the same heads. there are quite a few threads about on these
If done properly & successfully - I would love to hear an active pair of 802's.
However if I owned a pair, I don't think I would 'mess' with them - BUT
embark on a separate dedicated active project. (money?)
However if I owned a pair, I don't think I would 'mess' with them - BUT
embark on a separate dedicated active project. (money?)
I will some searching to see if I can find Serge's conversion. Even today 40+ years the fibrecrete midrange head and tiny tweeter have some merit. One reason this old speaker is still worth playing with....I think. I typically prefer the sound of fabric domes so though the limitation of the tweeter might be a bonus. The 802s will be aided in the bottom with my current RSS390 sealed subs that are already DSPed.
The conversion is done separately outside. The passive crossover is removed intact and the leads to the crossover is tapped to the outside to make the connections to the amps. Literally no modifications are made and all is totally reversible. So if one decides to reverse the actions it is easily done.
The conversion is done separately outside. The passive crossover is removed intact and the leads to the crossover is tapped to the outside to make the connections to the amps. Literally no modifications are made and all is totally reversible. So if one decides to reverse the actions it is easily done.
Is it possible to determine the filter transfer functions of the MiniDSP by feeding it with filter coefficients?