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  1. How can I connect a microphone with jack cable to the line-in port of a simple speaker, please? How can I adjust mic level to line level?

  2. Similar question: How can I adjust line level of CASIO SA-46 to line level of a mixer?

closed as off-topic by Rory Alsop May 29 '18 at 6:56

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions that are related to consumer audio consumption (such as audiophile or home theater) are off-topic. For more information, see the meta post on Non-Production Questions." – Rory Alsop
If this question can be reworded to fit the rules in the help center, please edit the question.

  • A microphone preamp is a device that takes a mic-level signal and brings it to line-level – Timinycricket Apr 27 '18 at 4:32
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First of all, I believe this is off-topic as it is about consumer grade equipment. However I will give an answer to those 3 questions

From OP:

How can I connect a microphone with jack cable to the line-in port of a simple speaker (swbtsp200bl), please? How can I adjust mic level lo line level, in genereal and in this specific case?

Similar question: How can I adjust line level of CASIO SA-46 to line level of a mixer (xenyx-802)?

From Comments:

I'd like to understand why there is no mic on the market with built-in preamp. If I want to connect a mic to a speaker.

In order to understand "line-levels", we first have to make a definition what these are. And for that we need to recognize that there are 2 types of line level, to be called "Proffessional" and "Consumer".

For Consumer grade equipment the nominal line level is expressed as -10dbV (= 0.316 Vrms). For Proffessional grade equipemtn the nominal line level is expressed as +4dbU (= 1.228 Vrms)

From this you can see that the levels are actually quite different.

Keeping this in mind, lets answers some questions:

How can I connect a microphone with jack cable to the line-in port of a simple speaker (swbtsp200bl), please? How can I adjust mic level lo line level, in genereal and in this specific case?

As you have not specified what brand/type microphone you are using, nor specified what cable, other than "jack"; this question can only be answered "in general" and not "specific".

In order to connect "any" microphone to "any" equipment, you need to ensure three things:

  • Ensure the "level" is correct
  • Ensure the "balance" or "unbalance" of the connection is correct
  • Ensure that the impedance of the two are matching

Looking at the datasheet of mentioned speaker the problem is that non of this is specifically mentioned. The following are just simply assumption due to lack of factual information.

  • The level of input is likely to be "consumer grade" nominal -10dbV
  • the balance of the connection is unbalanced
  • I don't even dare to have a stab at impedance...

Given your question, I would like to suggest that you source a "consumer grade" microphone, with some sort of pre-amp built-in. I am sure they are available, but I will refrain from listing examples, as this type of equipment is not my strong point. Another option is to source a little "consumer grade" pre-amp.

Similar question: How can I adjust line level of CASIO SA-46 to line level of a mixer (xenyx-802)?

So if you look at the Casio manual You will see it only has a head-phone output, with the following characteristics:

enter image description here

Great, we do have a specification, and based on the fact that this is a head-phones output, it is a stereo-unbalanced-signal.

Checking the manual of the Xenyx, the stereo inputs ch3/4 or ch5/6 can indeed take an unbalanced signal, you do need a "splitter cable" from the "stereo-jack" to "two mono jacks" for this to connect.

You will find the specifications on page-11:

The input impedance of the mixer is about 20k Ohm. This is quite high if you plug in something with an impedance of only 82 Ohm's.

While the Vrms is comparable, you are still trying to connect a "head-phone" out to the "stereo-line-in" of the mixer. Personally I find the source impedance a bit low, to give you the advice to plug this in.

My advice, please pick up the phone to Xenyx Technical support and ask them about this. My gut feeling says, it is OK, but I cannot give you a definite answer on this.

I'd like to understand why there is no mic on the market with built-in preamp. If I want to connect a mic to a speaker

This answer is very simple, there are many professional speakers on the market which will take balanced/un-balanced microphone inputs. Obviously if you buy speakers with "more features" you need to expect to pay "more money".

  • @KBen Also I would like to add that a direct box box is made for a few purposes and one of them is to take a high impedance input and convert it to low impedance. So you could use a DI box to match the impedance from the keyboard to the mic inputs of your mixer. – Timinycricket May 7 '18 at 21:30

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