Connecting a SUB to an AMP

strz · « **on:** 11 Apr 2016, 03:37 pm »

Hello gentlemen, please excuse my foolishnes for asking this.
I'll try to make this as short as possible.

I got a Pioneer SX-20K Stereo AMP, with 2 speakers connected via loudspeaker wire (i think thats how its named)
i want to buy a SUB like Jamo SUB-360, or 550, that has a LINE IN.

Please, explain to me HOW do i connect it to my AMP, english is not my native language, im not familiar with the audio terminology

Please excuse me for being a d--k, by reggin here and asking for help right away.

opnly bafld · « **Reply #1 on:** 11 Apr 2016, 10:01 pm »

Something like this to convert speaker level to line level
http://www.crutchfield.com/S-QP39rJVkXXH/p_543ADP12/Russound-ADP-1-2-Speaker-level-to-Line-level-Adapter.html

.............or you can buy a subwoofer with speaker level inputs.

Letitroll98 · « **Reply #2 on:** 11 Apr 2016, 10:02 pm »

You have a receiver, not an amp per se. Normally a receiver has an LFE out that goes to the subwoofer, but from the pictures I see online it doesn't look like your unit has that, or preamp outs. The only way you could hook a sub up would be if it has high level inputs, i.e. they look like speaker wire connectors and have in and out lugs. Then you run the speaker wires to the sub from your receiver, then another set of speaker wires from the sub to the speakers.

strz · « **Reply #3 on:** 12 Apr 2016, 11:00 am »

Excellent, now it makes sense.
So, the easiest thing i could do is just to buy a SUB with speaker level inputs, apparently.

Massive thanks for the help gentlemen !

p.s. i see the Jamo Sub-550 has speaker level inputs .

mresseguie · « **Reply #4 on:** 12 Apr 2016, 12:58 pm »

Strz,

No need to apologize. There are many folks here who offer their knowledge, experience, help, and services. I started out the same way you have. I still ask questions.

Michael

strz · « **Reply #5 on:** 12 Apr 2016, 02:05 pm »

Im very grateful for the help.

I just tend to be more polite, because in my country's forums, asking this type of questions renders you as a stupid ret**ded sh*t.

mresseguie · « **Reply #6 on:** 12 Apr 2016, 02:09 pm »

I understand because there are many online forums that allow attacks and abusive behavior. We try to prevent that here.

srb · « **Reply #7 on:** 12 Apr 2016, 03:52 pm »

On some subs with speaker level inputs, there are 4 pairs (In and Out) of binding posts (or spring clip connectors ... yuk!), to enable an internal high-pass filter on the main speakers to relieve them of some bass duty. In that case you would have no choice but to wire from amp to sub, then on to main speakers.

But if you don't need/want to high-pass the main speakers, or in this case where there is no internal high-pass filter, it's best to parallel the speaker wires directly off the back of the amp to keep the total main speaker cable run shorter. Rather than trying to stuff two wires under the post screw, it usually makes more sense to use one set of wires with bare wire or spade ends, and the other set terminated with banana plugs inserted into the end of the post.

Steve

strz · « **Reply #8 on:** 12 Apr 2016, 04:56 pm »

Steve, not sure what you just said, gonna reread it again.

BTW, i think i found myself a SUB, the JAMO Sub-550. The Sub has speaker level inputs.
So i think im just gonna leave my current two speakers connected to my amp. Since i have to connect the SUB to the AMP for the audiosignal, im just gonna do that.

Speakers -> AMP
Sub -> AMP

The two speakers are 3 range speakers (i think this is the right terminology), i just need that extra lows for my House music.

Letitroll98 · « **Reply #9 on:** 12 Apr 2016, 07:26 pm »

No, you connect the amp to the sub, then the sub to the speakers. I'm pretty sure the Jamo has an internal crossover that splits the low frequencies to the sub, then sends the higher frequency signal to the speakers.

srb · « **Reply #10 on:** 12 Apr 2016, 07:38 pm »

Quote from: Letitroll98 on 12 Apr 2016, 07:26 pm

No, you connect the amp to the sub, then the sub to the speakers. I'm pretty sure the Jamo has an internal crossover that splits the low frequencies to the sub, then sends the higher frequency signal to the speakers.

No, the Jamo SUB 550 only has L+R speaker level Inputs, there are no speaker Output connections.

http://www.jamo.com/docs/common/SUB550/SUB550_OM.pdf

Quote from: strz on 12 Apr 2016, 04:56 pm

The two speakers are 3 range speakers (i think this is the right terminology), i just need that extra lows for my House music.

"3-way"

Steve

Letitroll98 · « **Reply #11 on:** 13 Apr 2016, 02:19 am »

Your right Steve, I was looking at another model and assumed. The op should buy a different sub then. You know, one that hooks up the way I say it should.

Seriously though, isn't running two sets of wires from the receiver to the speakers and the sub a parallel connection, lowering the impedance by half, and possibly risking damage to speaker and amp?

opnly bafld · « **Reply #12 on:** 13 Apr 2016, 02:23 am »

No, speaker level inputs have a very high input impedance so your amp only "sees" the main speaker impedance.

srb · « **Reply #13 on:** 13 Apr 2016, 02:48 am »

Quote from: opnly bafld on 13 Apr 2016, 02:23 am

No, speaker level inputs have a very high input impedance so your amp only "sees" the main speaker impedance.

That's true. For some reason REL subs (who strongly recommend speaker level inputs vs. line level inputs) feel you need a super high input impedance (100K ohms) to have zero effect on the mains. But really, even with the Jamo SUB 550's input impedance at a "lowly" 22K ohms in parallel with an 8 ohm main speaker load, the total parallel resistance is 7.997 ohms (and 3.999 ohms with 4 ohm main speakers)!

As far as high passing the mains, my own experience has been that if you can play your mains full range at the volume you want without undue distortion or strain, then you shouldn't really high-pass them. The low E of a 5 string bass guitar has a fundamental of 40Hz, so not messing with another crossover in that region if you don't have to makes sense.

So normally if that's the case, I'll run the mains full range and add just a little somethin' extra somewhere around 60Hz or below.

Steve

strz · « **Reply #14 on:** 13 Apr 2016, 05:51 am »

Wait... so is the JAMO 550 gonna work now or not?
I do not want to connect my speakers to the JAMO, they gonna be connected to the AMP, im fine as they are.

I thought i just had to connect the AMP to the JAMO via those INPUT connections and i get audio signal to it.

srb · « **Reply #15 on:** 13 Apr 2016, 06:16 am »

Quote from: strz on 13 Apr 2016, 05:51 am

Wait... so is the JAMO 550 gonna work now or not?

Yes, it will work. Main speakers and subwoofer will both connect to speaker outputs of amplifier.

It usually takes a bit of trial and error to find the best settings for input level (volume), crossover frequency and phase control. You will also get varying bass response with the location of the sub. If you have the flexibility to try it in different locations, do so. The corners of the room are usually the worst location.

Steve

strz · « **Reply #16 on:** 13 Apr 2016, 06:40 am »

Oh... in that case, fk yes !
Gentlemen i can't express my gratitude !

On my "local" forum all i got was "You can hook it up anyway you want."

THANK YOU !

strz · « **Reply #17 on:** 13 Apr 2016, 06:58 pm »

Gentlemen, quick question, sorry for double posting

I bought a second hand JAMO SUB-550 (dont have more than 150usd)

What should i look for when i test it out, to make sure everything is alright?
Any tips are more than welcome

srb · « **Reply #18 on:** 13 Apr 2016, 07:47 pm »

You can play some test tones to check that the driver and amplifier are working correctly and not making any weird noises or heavy distortion. That will also help check that nothing is physically loose or vibrating with the cabinet, driver and amplifier.

You can feed test tones higher in frequency than the crossover setting on the sub to make sure the crossover control is working properly.

The crossover filter is not a "brick wall" filter, there is some kind of slope, maybe 12dB/octave or 24dB/octave (?). But if you have the sub set to 60 Hz I wouldn't expect to hear much of a 120 Hz tone and certainly not a 200 Hz tone.

You can download a variety of test tones, both variable sweeps and individual tones. If you don't have a computer connected to play the downloaded test tones, you can burn them to a CD. There are many sources, but one is audiocheck.net. You can see there are many test files for checking other aspects of system performance, but the ones most applicable to subwoofer testing would be

Sound Tests and Audio Test Tones
http://www.audiocheck.net/soundtestsaudiotesttones_index.php

Frequency Response Tests:
Low Frequency Response and Subwoofer Audio Test (10-200 Hz)
Subwoofer Midrange Frequency Test
Subwoofer Kick Test

Distortion Tests:
Low Frequency Extension and Subwoofer Harmonic Distortion Test (THD)

Stereo Imaging Tests:
Low Frequency Sound Localization and Subwoofer Imaging Test

You can also download individual Sine Burst Tones (20-200 Hz)
http://www.audiocheck.net/testtones_sinebursts20-200.php

Steve

strz · « **Reply #19 on:** 14 Apr 2016, 01:04 pm »

Steve, You da MVP mane !

So, gentlemen, i bought the SUB (JAMO 550), im honestly very happy with it.
i tried some of the tests that Steve provided and...
this is the first time my i heard my persiennes[ty google translate] tremble/shake from the bass.

All is well gentlemen, thanks to all of your advice i got myself a good sub for ~150€