Thoughts on bi-amping speakers.

Beefalo · Jan 5, 2020

When I was into car audio the high end systems had active crossovers. Content was split into 4 adjustable ranges. Sub, mid bass, mid & tweeter. We would also adjust the roll off slope. 24db was the most common.
You could fiddle around forever and find what suited your system and tastes.
It was too much fun.

jimfisheye · Jan 5, 2020

Ken61 said:
Hello,

I'm in the process of upgrading and just looking for some thoughts on bi amping. I picked up an Oppo bp-83 and grabbed a low end receiver to get the HDMI connections. I'm going to replace it probably next year. But in my reading I notice some av reciever offer the feature on their 7.x equipment to run a 5.x system and use the extra outputs for bi-amping.

I know on low end speakers the quality of componets are questionable, particualry the passive cross over. And bi amping can be a real improvement. But with the mid price ranged speakers where the quality is much higher is it much of an improvement?

Thanks,

Ken

Well, it would be the passive crossover vs either an active one or dsp. (The receiver may handle the crossover eq digitally - Digital Signal Processing.) My guess is the receiver would almost certainly do the crossover with dsp rather than switching active crossover circuits into the analog signal path post DA conversion. So... it would be that vs whatever the passive crossovers in your speakers are. The dsp would be flexible in that you could dial in any crossover point you wanted - erm... within the control features allowed anyway! A receiver isn't exactly a DAW on a computer! You would have to mod the speakers with inputs to each driver, bypassing the passive crossover. Depending on the feature set of the receiver and how good the dsp is, I wouldn't be shocked if the passive crossover was better in a pinch. I'm fully onboard with digital audio and of the opinion that some digital signal handling is better than analog, mind you! But dsp on the cheap is grainy and awful. Cheap dsp crossovers could lose a shootout like that pretty quickly.

gene_stl · Jan 5, 2020

I have doubts about whether DSP would be grainy and awful. It is quite difficult to set up A/B testing of such things. If you don't want to do it in the digital domain (which I have not done yet though I have a stack of four Crown CTs series amps that have DSP input modules that do a whole bunch of tricks , probably everything that mini DSP and many others do. I believe they have SHARC processors) you can always buy analog crossovers which are also very reasonably priced.

https://www.parts-express.com/art-cx311-stereo-2-way-crossover-with-sub-out--245-862
https://www.xkitz.com/collections/active-crossovers-and-bi-amplifiers-1
https://www.ebay.com/itm/2-Ways-24d...a=0&pg=2047675&_trksid=p2047675.c100005.m1851
https://www.sweetwater.com/store/de...drive-dcx2496le-loudspeaker-management-systemthis one is digital also but is known to sound very good. and measure very well.

https://www.sweetwater.com/store/detail/DriveRack260--dbx-driverack-260these are also digital and will run a stereo three way. There are two lower priced models. This pricier model is aimed at high end audio systems. I have a friend here in st.louis that drives a pair of Martin Logan Electrostats with one.

Of course if you can get your hands on one of these You have it made!
https://www.ebay.com/itm/Pioneer-D-...609106?hash=item28848e48d2:g:zp4AAOSwRsddYWv4

I will try and step off of the soapbox. However this is actually my most favorite subject. (too late for me to get a life)

Beefalo · Jan 11, 2020

Have you heard of - Outlaw Audio ICBM-1 Analog Bass Management / Multi-Channel Active Crossover?
You can run DSD straight without converting to PCM if you have an older universal player with analog outputs. Then into separate amps.
I believe you would still be using the passive crossovers in the speakers though.

gene_stl · Jan 11, 2020

I was not aware of the 2001 vintage unit.

https://hometheaterhifi.com/volume_8_4/outlaw-audio-icbm-bass-management-11-2001.html

Above is an very nice review of it. It includes photographs of the interior. I counted 20 op amps. Yet it only sells for $250 (sold?) It seems to be intended to offload work from a DSP in a pre processor.
or in player that doesn't have bass management and crossover outputs.

It would substitute for two stereo plus one mono crossover network. It only allows bass/lfe biamping which is certainly better than no biamping. I guess I really like tri amping and quad amping better.
But doing it in MCH does start to be quite a committment. Even the above review refers to 15 rca cables coming out the back of the unit.

The way you did it in car audio works great in the listening room. There are a lot of equipment boxes sitting around. You need good racking.

jimfisheye · Jan 11, 2020

gene_stl said:
I have doubts about whether DSP would be grainy and awful...

CHEAP dsp is grainy and awful.
The average consumer receiver. Budget amps with built-in dsp. (Especially the smaller budget powered speakers aimed at DJs.) Pretty much anything sold in Worst Purchase - the grifter stuff.

Pro quality dsp will outperform everything but the highest end analog - which it will usually match!

Just understand how the gear works and what you're doing. Don't end up with some Rube Goldberg mess of extra AD and DA conversions and/or dsp moves in one piece of gear battling some setting you weren't even aware of in another and that kind of thing.

For any passive speaker in question:
It will have a passive analog crossover. If you wanted to have a shootout between that and an active crossover and bi-amping, you'd have to modify the speaker with direct connections to the drivers. Then build your system with an active analog crossover fed from your DAC output. Which then connects to two amps and then to the two drivers (a 2-way speaker example). Or... A digital crossover. This would then need to connect to two sets of DAC outputs. Then to amps and to speakers.

If you had powered 2-way speakers, they likely have an active crossover before the amps. To have a shootout with different crossover and amps you'd have to mod them to make two inputs, one directly to each amp.

Think of some of these products as "combo" devices. Like a receiver is: HDMI audio interface, DA converters, analog preamp, power amps. Powered speakers are: Passive speaker (with passive crossovers) with power amp built in. Bi-amp'd powered speakers are usually: passive speakers with active crossover and two amps built into the box.

Take inventory carefully and don't buy two of something inadvertently!

The Rube Goldberg stuff that ends up with multiple back and forth AD/DA conversions and/or improper levels/ranges with analog connections throws the intended performance and spec out the window! We're into generational loss and edge case madness with that.