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I have a small analog mixer, a Xenyx Q802usb, with two 1/4" speaker outputs. The venue I'm considering would be a small coffee shop that can get slightly louder than we can overcome with our acoustic sound.

Rather than taking speakers and cables to the gig, I would like to take some smaller Bluetooth speakers with me, like a handful of the JBL Flip 4's. The Flip 4's can connect to one another so I could distribute several of them around the room so we a) don't blast out the folks right in front of us and b) folks in the back of the room can hear us. We're just looking to augment our sound a small amount to overcome some room noise.

What's the best option to send my mixer's speaker-out signal to Bluetooth speakers?

  • How much delay are you prepared to accept? Bluetooth is not real-time, it has significant latency. – Tetsujin Jun 27 '18 at 18:45
  • Please update your question with the brand and type of your mixer – Edwin van Mierlo Jun 28 '18 at 8:43
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    Please update your question with the type of venue, size and type of room (with bar, without bar, open air, other), and what type of audience (general people hanging out for the evening, dedicated audience sitting still to listen, other) ... and any other information you can share about your performance. This will greatly help to get accurate answers. – Edwin van Mierlo Jun 28 '18 at 8:46
  • As convenient as wireless audio is, I think it says something that no manufacturer of professional music equipment has released a wireless PA product. The reliability and sound quality just aren't there, even for smaller gigs. – Todd Wilcox Jun 28 '18 at 13:51
  • @EdwinvanMierlo, I've updated my question with some more details. Thanks for the already thoughtful answer! – Mark A Johnson Jun 28 '18 at 17:29
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There are various concerns which need to be addressed with the solution you are proposing.

Power output of the JBL Flip 4:

From the specification here the JBL Flip 4 speakers are stereo speakers with a max power output of 2 x 8 Watts. The harmonic distortion of this speaker is unfortunately not listed in the specification, but one may assume that there is some distortion while operating at maximum power output.

Although I hate doing this, lets assume that you can operate the unit without noticable distortion at 2 x 6 Watts, which brings the total power output of the device to 12 Watts.

It depends on the venue, the activities in the venue, the activities of the audience in the venue, on how much power you really need.

Example: for a small venue, as you describe, you probably need about a 100 Watts of amplification. This is an estimate, YMMV. But given this, you will have to bring 9 or 10 of those devices.

Frequency response and SPL:

Once we have enough devices for the size/type of venue and we have enough power, that does not mean that the quality of the sound is actually acceptable. The JBL Flip 4, and similar devices, are really designed for near field listening in small rooms. The question is how accurately is this device responding to various frequencies, especially critical is the low frequency roll off, and the high frequency roll off. The specification (link above) is not really giving us this information, other than the device has a frequency reponse of 70 Hz to 20 kHz. While this looks good on paper like that, it surely does not mean that you have a good "Sound Pressure Level" (SPL) for low or high frequencies.

One would safely assume that the SPL and performance of such a device for low and high frequencies is questionable at best, and likely unacceptable.

I found a review which notes:

  • "One of the problems of reviewing the performance of these small Bluetooth speakers is that their sound quality isn't consistent."
  • "it doesn't play quite as loud or have as good battery life"

A multiband equalizer may be need to try to compensate for bad frequency response. But even those would be limited at some point.

Multiple device streaming setup:

For the purpose of this section we call the Flip 4 a "Bluetooth Client" as it receives the signal, and the unit broadcasting "Bluetooth streamer".

We need a Bluetooth Streamer between your mixer and multiple Bluetooth Clients, as we have already determined that we need 9 or 10 of those units at a minimum.

It would be common for many Bluetooth streamers to be able to stream music to one, and only one, Bluetooth Client. Bluetooth streamers who are able to stream to multiple Bluetooth Clients are available, but are more expensive. Most of those Bluetooth streamers are designed for music streaming from a recorded source, internet streaming, USB dongle, CD (oh lord; I am showing age am I), and designed for music reproduction in a non-latency-critical environment, at home, in a restaurant, somewhere where a delay is not critical.

I have never tested this myself, so the following list of concerns are theoretical, but probable:

  • There is a delay of the Bluetooth streamer, from time the signal is received on its input, and the signal is transmitted over bluetooth
  • There is a delay in the actual (radiowave) bluetooth signal between Bluetooth streamer and Bluetooth clients
  • There is a syncronious delay between the multipe Bluetooth clients, which could lead to the Bluetooth Clients being out of phase. They do play the same music, just not at the same time
  • There is jitter and pauses; due to multiple Bluetooth Clients connecting to the same Bluetooth streamer, you could find congestion on the Bluetooth "channel" which will lead to "jitter and pauses" which can cause the Clients or the streamer to buffer some of the raw-data. This could lead in pauses in the music reproduction, and worse: these pauses would differ from Client to Client, so one Flip 4 could stop while others continue, the the stopped unit resumes and lacks behind in music reproduction, being out of phase or worse: multiple seconds behind.

Connections from mixer to JBL Flip 4:

The mixer you have does NOT have "speaker outputs" as you claim in your question. The Xenyx Q802usb has the following outputs which can be used for a connection to a Bluetooth streamer:

  • Main Out:
    • Level: Line Level Pro Audio, +4dBu
    • Type: balanced, TRS-1/4"-Jack
    • Vpp = 1.736 V
  • 2 Track Out:
    • Level: Line Level Consumer, -10dBV
    • Type: unbalanced, RCA
    • Vpp = 1.414 V

What you need to do is:

  • find a Bluetooth streamer, which is capable of streaming to multiple JBL Flip 4's.
  • ensure that you know the upper-max limit of number of devices you need to stream to, to determine if you need more than one streamer.

Once you have found your streamer, ensure you know what type of connections they take.

  • if they take RCA/consumer-line unbalanced-inputs, then connect them to the 2TR outputs of your mixer
  • if they take TRS-1/4"-Jack pro-audio-line balanced-inputs, then connect them to the Main Outs of your mixer.
  • if the above two are not applicable, then you need to ensure the line-level is correct, and it is unbalanced or balanced. The permutations are to many to list them all, best to ask the manufacturer of the Bluetooth streamer.

If you need more than one unit, then you need to split the L-R signal, from either the Main-Out or the 2TR-out to multiple signals. There are many signal splitters on the market, to many to list.

Now an example: please note that I do not have any affiliation with this company/brand/website... here goes

As you can see this is getting more and more complex to setup, with each component at risk of failing, latency, out of sync, interference.

Disclaimer: I do not guarantee anything here, I do not know if these devices/equipment work together to get good quality sound, or at all... This is just an Example. For my opinion; please see my conclusion.

I would have serious doubts running 5 Bluetooth streamers simultaneously in close proximity, all connecting to 2 devices, that is a lot of traffic on the Bluetooth frequencies, it will lead to congestion, collisions, and connectivity issues. Even if you can distinguish which streamer you connect to from your client, they may be indistinguishable, and have the same name.

Cost:

You will have to keep track of what you want to spend on such a solution:

  • Multiple JBL Flip 4's: probaly 10 or more, including some spares
  • Bluetooth Streamer, or multiple, depending on how many devices can connect to one unit
  • cabling between Mixer and Bluetooth Streamer(s), signal splitter if multiple streamers are needed
  • spares, chargers, spare batteries
  • possible multiband equalizer to at least try to compensate for bad frequency response

Opinion / Conclusion:

What can I say other than: do not do this, as in my opinion you cannot remediate all mentioned concerns reliably.

I estimate that you are going to drop about $500 to $2000 to make this all work very badly, if it works at all.

Conclusion:

If you can overcome the above concerns, reliably, then you can use a number of JBL Flip 4's for live sound reproduction.

(if you think you can, I would be amazed and would love to know how you do that)

  • A fantastic analysis, Edwin! Thanks for the time you put into this. One thing that drew me to the JBL Flip 4 is their "Connect+" feature. I haven't explored it yet (since I have only one), but my understanding is that once I connect to a single speaker via Bluetooth, their Connect+ protocol links the first to up to 99 more speakers. I can only assume latency between speakers should be very small or the advertised system would be unusable. If that's true, I only have to deal with the latency to the first. After reading your response and comments, that's a primary concern. Thanks, again! – Mark A Johnson Jun 29 '18 at 14:36

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