• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Looking for a good A/B switcher for blind listening tests

richard12511

Major Contributor
Forum Donor
Joined
Jan 23, 2020
Messages
4,335
Likes
6,700
I'm really interested in getting back into blind listening tests, but I want to improve my process a bit from how I've done it in the past. I'm looking for a speaker switcher that can switch quickly between either two mono speakers or two stereo pairs. I also want the ability to equalize the bass by using at least 2 subs. Also, a switcher that could support 3 speakers at the same time would be preferred.

This is the only one I know of atm. Any other suggestions? I'm no good with DIY, but if someone wants to guide me through making something, I could do that.

Recently I purchased the Genelec 8030c and the Magnepan LRS, and that's kinda the impetus for this. I'm starting to get a pretty good collection of different speakers, and I'd love to start comparing them in a more objective manner.
 

restorer-john

Grand Contributor
Joined
Mar 1, 2018
Messages
12,579
Likes
38,278
Location
Gold Coast, Queensland, Australia
Considering the low demand for such a product, the AVA, although limited in the number of items it can connect, it does appear to be good value.

It does appear to use the preamplifiers to level set however. It may not be able to level match integrated amplifiers against one another.

If you just want to switch between speakers and sources without the full ABX testing, you could build something quite inexpensively.
 
OP
richard12511

richard12511

Major Contributor
Forum Donor
Joined
Jan 23, 2020
Messages
4,335
Likes
6,700
Considering the low demand for such a product, the AVA, although limited in the number of items it can connect, it does appear to be good value.

It does appear to use the preamplifiers to level set however. It may not be able to level match integrated amplifiers against one another.

If you just want to switch between speakers and sources without the full ABX testing, you could build something quite inexpensively.

Since I'll only be using this for speakers, I'll just be doing preference testing, so I may not need the ABX stuff. I'd definitely be down for DIY, but I just have no idea where to even start on that.
 

Bob-23

Senior Member
Joined
Jul 3, 2019
Messages
425
Likes
379
Location
Berlin, Germany
I'll just be doing preference testing, so I may not need the ABX stuff.
I think so, too. In my experience, a simple A-B switch box does a quite good job, with or without relay. Years ago, I built one according to Rod Elliott resp. Phil Allison with relays - but for a beginner it might even be too difficult. A simple double-pole-double-throw (DPDT) - switch a little box should do it, too. But there should be lots of these boxes on the market.
Rod Elliott's great ESP: https://sound-au.com/

Instantaneous switching done by such a box is necessary - at least when the differences between the sources are potentially minimal - because our accoustic memory is extremely short. Plugging in and out would already take too long.

You need a sensitive multimeter in order to equalize loudness resp. voltage of both of the sources, as adequately as possible. Take a 400 Hz test signal from Youtube, both amps shouldn't differ by more than 1 %. Even very slight loudness differences which are not yet discerned as such, are perceived as 'more open', 'better' sounding.

You can even do the switching quasi 'blindly' by obfuscating before yourself which position of the toggle switches which amp - e.g. you may let somebody else connect the box to the amps and cover the cables or you twist the cables leading to the box...

But, as it switches seamlessly you usually get it immediatley if there's a difference, or not.

You'll probably have surprising and potentially 'shocking' results.
 

Chromatischism

Major Contributor
Forum Donor
Joined
Jun 5, 2020
Messages
4,765
Likes
3,703
Can you elaborate on this? I've got 3 AVRs here, though only two with preouts to support active designs.
Sure. This won't support instant switching, but the delay is only about 2 seconds. It's what I've come up with using the gear I have.

Connect one speaker to front right, and the other to surround right (or use front and surround left, it doesn't matter).

Use the Levels menu to adjust levels to be as equal as possible.

Use a source that can mix stereo channels to the surrounds. I use foobar with a DSP plugin and set a hotkey to turn it on or off. This is running on my laptop PC and connected with HDMI.

Optionally, you can use a DSP that mixes both channels to mono and run that while switching. I didn't care for it but it's an option. Basically you're using the player source as your switcher in lieu of hardware. I just sit back and switch using hotkeys, while using another hotkey to rewind 10 seconds. This way I can listen to the same passage repeatedly with either speaker. I can post screenshots later if interested.
 

SerpensCaput

Member
Joined
Sep 23, 2020
Messages
7
Likes
2
Location
( ⚆ _ ⚆ )
Since I'll only be using this for speakers, I'll just be doing preference testing, so I may not need the ABX stuff. I'd definitely be down for DIY, but I just have no idea where to even start on that.

I think if it's just simply for the purpose of selecting speakers something like Taga Harmony TS-4 could do, it's inexpensive and does the job. The question is if you're bothered with the components you introduce directly into the signal path.

Edit. also, if you can use it at all will depend on your amplifier power output
 
OP
richard12511

richard12511

Major Contributor
Forum Donor
Joined
Jan 23, 2020
Messages
4,335
Likes
6,700
Went ahead and purchased the Van Alstine. I figure it's a worthwhile investment for future purchases for which I can demo.

Not sure I'm still getting the LRS(they never replied to my purchase request) but I'll definitely be using it to compare Genelec 8030c/Revel M105/JBL 308p.
 

restorer-john

Grand Contributor
Joined
Mar 1, 2018
Messages
12,579
Likes
38,278
Location
Gold Coast, Queensland, Australia
Went ahead and purchased the Van Alstine. I figure it's a worthwhile investment for future purchases for which I can demo.

I think you'll be happy with it. Even down the track, when AVA has stopped making them, you'll have a valuable device that may end up worth as much or more than you paid for it.

Why don't you do a review of it here on ASR?
 

pma

Major Contributor
Joined
Feb 23, 2019
Messages
4,591
Likes
10,727
Location
Prague
I have wiped of the dust from my old simple A-B box which is able to switch outputs from 2 stereo amplifiers to one pair of speakers. I was interested in the inserted distortion and attenuation with the A-B box. There was no distortion issue found, however there is some attenuation when the box is inserted into the signal path. Signal at the box input was compared to box output. The drop in level may be attributed to relay contact resistance and banana plugs/binding post resistance. However it seems not to be critical. The plots below show signal attenuation at 2 different voltage levels.

Voltage infrontof-behind A-B box.png
 

amper42

Major Contributor
Joined
Dec 21, 2020
Messages
1,582
Likes
2,284

DVDdoug

Major Contributor
Joined
May 27, 2021
Messages
2,917
Likes
3,831
Speaker switching probably doesn't have to be blind because with speakers there is usually an obvious difference in sound and you'll know which-is-which anyway.

If you didn't know anything about the speakers a blind test could be helpful because you wouldn't know the cost, manufacturer, or appearance and it would allow you to judge more fairly.

Instantaneous switching done by such a box is necessary - at least when the differences between the sources are potentially minimal - because our accoustic memory is extremely short. Plugging in and out would already take too long.
Instant switching is "best" if it's hard to hear a difference but if you are comparing equipment and you can't hear a difference after a couple of seconds or minutes, does it really matter? ;) I'm not going to upgrade my speakers or amplifier if I can't hear a difference the next day...

An ABX test (again probably not necessary with speakers) requires you to "fake" a switch when you're actually not switching but comparing A-to-A or B-to-B. That generally means you need an off-position or a separate on-off switch or if you are manually connecting/disconnecting you have to disconnect every time.
 

pma

Major Contributor
Joined
Feb 23, 2019
Messages
4,591
Likes
10,727
Location
Prague
I was thinking of using the SOLUPEAK P2 2(1)-in-1(2)-Out Amp Switcher between the Purifi and the Buckeye NC502MP amp with the Revel F328Be.


As almost always, not enough info. I would not buy anything like this without knowledge which relays are used inside. Just FYI, a good relay for this purpose costs 10 EUR/pc. Just one relay.
 

Chromatischism

Major Contributor
Forum Donor
Joined
Jun 5, 2020
Messages
4,765
Likes
3,703
I think the best "switching" isn't really switching at all, but having both channels playing the same content, and alternating the mute control at the electronics (but not source) level. This would take a little more electronics, though. Two DACS, at least.
 
OP
richard12511

richard12511

Major Contributor
Forum Donor
Joined
Jan 23, 2020
Messages
4,335
Likes
6,700
Forgot to update this thread. I ended up buying the AVA ABX Switcher. Expensive, and I'm sure if I knew what I was doing I could make something for much cheaper, but I don't, and I like the fact that it allows me to switch between 3 speakers with or without subwoofers in play.

Unfortunately, I haven't had a chance to use it yet :(, due in large part to COVID.
 

Attachments

  • image_123927839 (2).JPG
    image_123927839 (2).JPG
    183.3 KB · Views: 115

restorer-john

Grand Contributor
Joined
Mar 1, 2018
Messages
12,579
Likes
38,278
Location
Gold Coast, Queensland, Australia
I think the best "switching" isn't really switching at all, but having both channels playing the same content, and alternating the mute control at the electronics (but not source) level. This would take a little more electronics, though. Two DACS, at least.

You have to have a way of electrically isolating one amplifier output from another. High quality relays are the best way to do that. Otherwise the "driven" amplifier drives directly into the zero output impedance of the "undriven/muted" amplifier. Result? Bang! and a new set out output transistors, drivers and associated parts.
 

Chromatischism

Major Contributor
Forum Donor
Joined
Jun 5, 2020
Messages
4,765
Likes
3,703
You have to have a way of electrically isolating one amplifier output from another. High quality relays are the best way to do that. Otherwise the "driven" amplifier drives directly into the zero output impedance of the "undriven/muted" amplifier. Result? Bang! and a new set out output transistors, drivers and associated parts.
So you have one source going into two DACs by duplicating one of the outputs. You have either two right speakers or two left speakers coming from there, into their own amps. This doesn't need to be high-end gear, just enough to be transparent with adequate power. Then you just mute one DAC, then hit the mute button on both remotes to alternate which is playing. Music stays in sync because there is only one source.
 

restorer-john

Grand Contributor
Joined
Mar 1, 2018
Messages
12,579
Likes
38,278
Location
Gold Coast, Queensland, Australia
So you have one source going into two DACs by duplicating one of the outputs. You have either two right speakers or two left speakers coming from there, into their own amps. This doesn't need to be high-end gear, just enough to be transparent with adequate power. Then you just mute one DAC, then hit the mute button on both remotes to alternate which is playing. Music stays in sync because there is only one source.

Ah, you are talking about USB audio?

Because SPDIF can be sent to two D/As from either a split coax or twin outputs (Toslink and coax), or simply duplicated and looped out in several of my preamps with onboard D/As. I'm talking about switching speaker level outputs into one pair of speakers from multiple amplifiers.

:)
 
Top Bottom