Trying to hook a sub and rear speakers to one amp... Can this be done?

[alec14 10+ year member]

I gotta do an install on my cousin's Aztek, and I plan on putting new speakers in the back, with a good 10" sub as well. He wants to conserve space, and there's a pretty tight budget. I was hoping to run the sub and speakers off of one 2-channel amp, probably both the sub and speakers at 2 ohms. Can I do this? Would a 4-channel amp be better? I'm just wondering what my options would be. Any help would be great!

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[Sonic. 10+ year member]

4 channel.

 

[neo_styles 10+ year member]

You could find a three-way compatible 2-channel amp and make that happen, but you need to make sure it's 2-ohm stable bridged. Basically, in three-way mode, you're hooking up your rear speakers stereo (so one to each channel) and then bridging the sub across the same channels. Just takes some searching to find one that will support 2 ohm bridged...

 

---------- Post added at 08:26 AM ---------- Previous post was at 08:26 AM ----------

 

I think tri-mode is another term they use for it.

 

[alec14 10+ year member]

4 channel.

What makes a 4-channel more capable of helping me than a 2-channel? not meaning to sound rude, just didn't know how else to word that. I'm actually wondering

 

[alec14 10+ year member]

You could find a three-way compatible 2-channel amp and make that happen, but you need to make sure it's 2-ohm stable bridged. Basically, in three-way mode, you're hooking up your rear speakers stereo (so one to each channel) and then bridging the sub across the same channels. Just takes some searching to find one that will support 2 ohm bridged... 

---------- Post added at 08:26 AM ---------- Previous post was at 08:26 AM ----------

 

I think tri-mode is another term they use for it.

So, the speakers would have their own channels, but the sub would be using all 3 as well? I'm new to some of these more complex amps, lol

 

[neo_styles 10+ year member]

So, the speakers would have their own channels, but the sub would be using all 3 as well? I'm new to some of these more complex amps, lol

More or less

 

[n2audio 5,000+ posts]

Tri-mode isn't very practical -- especially considering the minor difference in price vs a capable 4 ch.

Any amp that's 2 ohm stable in stereo (not bridged) can be used in tri mode. It just requires a 4 ohm (or higher) pair of speakers, and a 4 ohm (or higher) sub.

Problems -- you have to use an in-line filter for both the speakers and subs which adds to the cost as well as the difficulty of the installation, especially for a novice. Plus -- unless it's a high power amp (requiring high power speaker) the power to the sub would not be much.

The speakers are connected as usual. The sub is then connected to the bridge terminals of the amp.

For example -- Say your amp is 100 x 2 at 4 ohms stereo, and 150x2 at 2 ohms stereo.

If the speakers and sub are all 4 ohms the resulting load on the amp would be 2 ohms stereo. The speakers would see 75w each and the sub would see 150.

You'd need a high pass filter for the speakers and a low pass filter for the sub. The crossover on the amp would be unused.

I've never seen it actually used, and it's not something I'll ever mess with.

In all my 10 yrs lurking on various forums I only recall one person that's actually done it and liked their results.

With a 4 channel amp you'd use 2 ch to run the speakers and the other 2 ch bridged for the sub (the sub needs to be either a single 4 ohm or dual 2 ohm voice coil).

In this case -- example - Amp is 75x4 at 4 ohms stereo, 100x4 at 2 ohms stereo.

Front speakers would see 75w, sub would see 200w. You'd turn on the high pass filter for the speaker channels, and low pass for the rears.

 

[Sub Bass Woofrz 10+ year member]

i think 5 channel. then the sub would have a dedicated channel with more power

 

[b-roccfordexpo]

What is the budget for this build? There are some decent amps on the market for good prices.

 

[Sub Bass Woofrz 10+ year member]

What is the budget for this build? There are some decent amps on the market for good prices.

that sig a joke?

 

[alec14 10+ year member]

More or less

okay, that makes sense. Thanks man

 

---------- Post added at 04:52 PM ---------- Previous post was at 04:51 PM ----------

 

i think 5 channel. then the sub would have a dedicated channel with more power

Only running one pair of speakers.... I don't wanna have wasted channels.

 

[alec14 10+ year member]

Tri-mode isn't very practical -- especially considering the minor difference in price vs a capable 4 ch.
Any amp that's 2 ohm stable in stereo (not bridged) can be used in tri mode. It just requires a 4 ohm (or higher) pair of speakers, and a 4 ohm (or higher) sub.

Problems -- you have to use an in-line filter for both the speakers and subs which adds to the cost as well as the difficulty of the installation, especially for a novice. Plus -- unless it's a high power amp (requiring high power speaker) the power to the sub would not be much.

The speakers are connected as usual. The sub is then connected to the bridge terminals of the amp.

For example -- Say your amp is 100 x 2 at 4 ohms stereo, and 150x2 at 2 ohms stereo.

If the speakers and sub are all 4 ohms the resulting load on the amp would be 2 ohms stereo. The speakers would see 75w each and the sub would see 150.

You'd need a high pass filter for the speakers and a low pass filter for the sub. The crossover on the amp would be unused.

I've never seen it actually used, and it's not something I'll ever mess with.

In all my 10 yrs lurking on various forums I only recall one person that's actually done it and liked their results.

With a 4 channel amp you'd use 2 ch to run the speakers and the other 2 ch bridged for the sub (the sub needs to be either a single 4 ohm or dual 2 ohm voice coil).

In this case -- example - Amp is 75x4 at 4 ohms stereo, 100x4 at 2 ohms stereo.

Front speakers would see 75w, sub would see 200w. You'd turn on the high pass filter for the speaker channels, and low pass for the rears.

This, sir, is the practical answer I was looking for. Thank you! I think I'll try not amping some speakers (I'll get some low power/high sensitivity ones), and just get a nice mono for the sub.

 

---------- Post added at 04:54 PM ---------- Previous post was at 04:53 PM ----------

 

What is the budget for this build? There are some decent amps on the market for good prices.

This is my problem. Everything I buy (excluding wiring, etc.) will be bought used.

 

[Bettr n' Revrse 5,000+ posts]

No since in wasting money to amp rear speakers...

 

[neo_styles 10+ year member]

okay, that makes sense. Thanks man 

---------- Post added at 04:52 PM ---------- Previous post was at 04:51 PM ----------

 

Only running one pair of speakers.... I don't wanna have wasted channels.

If they were 4-ohm speakers I'd say you could just bridge them on the 5-channel. Better to have the ability to upgrade your rears, though.

 

[alec14 10+ year member]

If they were 4-ohm speakers I'd say you could just bridge them on the 5-channel. Better to have the ability to upgrade your rears, though.

Well, I'm still pondering what speakers to get. They definitely need to be new ones though. If that's what you meant.