Genz Benz Streamliner; Part 4

[maurilio]

A little something about 4 and 8 ohm cabinets, as this comes up regularly and I get PM's about it too...

While many manufacturers strive to make their 4 and 8 ohm versions sound as close as possible, it should not be automaticly assumed that they will be identical. In fact, any time a designer alters one parameter of a speaker, others will need to be fuine tuned to bring the overall performance back to the original.

Changing the impedance is not as simple as plugging a different voice coil into the speaker, because the different voice coil will need to have a different wire gauge, winding length, inductance, sensitivity, DCR, weight, etc. All of these parameters, will need to be fine tuned along with the rest of the parameters to get as close to the same voicing as possible. As had as we try, they will not be identical. It should also be noted that some manufacturers don't even try to get their different drivers to sound the same, which is why you as a player should be careful when making assumptions, and where other player's experiences can help.

Also, an 8 ohm cabinet's sensitivity will be roughly 1/2 that of a 4 ohm cabinet when compared voltage-wise, and since all power amps are essentially an "ideal" voltage source, when you swap cabinets yo will experience an effective coubling of oiutput power when going from 8 ohms to 4 ohms without changing any of the controls on the amp. Perhaps this is what some of you have been experiencing?

Hey Andy, interesting. I've never thought of that, thank you.
I wonder, now, how my STL210 4ohms (custom) sounds vs. a standard 8

How's everything out there?

M

 

[husky123]

Thanks for that explanation! I don't feel like I'm going crazy now. All I know is that my identical GK cabs sound different going from 4 to 8 ohms even when I compensate for volume. And not just a little different...

A little something about 4 and 8 ohm cabinets, as this comes up regularly and I get PM's about it too...

While many manufacturers strive to make their 4 and 8 ohm versions sound as close as possible, it should not be automaticly assumed that they will be identical. In fact, any time a designer alters one parameter of a speaker, others will need to be fuine tuned to bring the overall performance back to the original.

Changing the impedance is not as simple as plugging a different voice coil into the speaker, because the different voice coil will need to have a different wire gauge, winding length, inductance, sensitivity, DCR, weight, etc. All of these parameters, will need to be fine tuned along with the rest of the parameters to get as close to the same voicing as possible. As had as we try, they will not be identical. It should also be noted that some manufacturers don't even try to get their different drivers to sound the same, which is why you as a player should be careful when making assumptions, and where other player's experiences can help.

Also, an 8 ohm cabinet's sensitivity will be roughly 1/2 that of a 4 ohm cabinet when compared voltage-wise, and since all power amps are essentially an "ideal" voltage source, when you swap cabinets yo will experience an effective coubling of oiutput power when going from 8 ohms to 4 ohms without changing any of the controls on the amp. Perhaps this is what some of you have been experiencing?

 

[agedhorse]

Thanks for that explanation! I don't feel like I'm going crazy now. All I know is that my identical GK cabs sound different going from 4 to 8 ohms even when I compensate for volume. And not just a little different...

Not crazy at all.

 

[agedhorse]

Hey Andy, interesting. I've never thought of that, thank you.
I wonder, now, how my STL210 4ohms (custom) sounds vs. a standard 8

How's everything out there?

M

Our drivers are very similar across the impedance differences, though not "identical" of course.

Good seeing you at NAMM.

 

[12bass]

What was weird to me is 2 identical cabs but one in 4 and the other 8 ohm sounding so different. Is it just one of those things or is it the SL is at max efficiency on the 4 ohm load?

Maybe the 8 ohm cabinet has the drivers wired out of phase? That would make it sound a lot thinner.

 

[KJung]

Thanks for that explanation! I don't feel like I'm going crazy now. All I know is that my identical GK cabs sound different going from 4 to 8 ohms even when I compensate for volume. And not just a little different...

Something a bit strange going on there. A little different, per agedhorse's comments, yes... but way different, not so much. Might be different drivers all together.

One thing that 'might' be happening is that the additional power is just overwhelming the GK cab and causing it to compress and reach its mechanical limits. Some of the higher end GK cabs are quite nice, but that lower end combo stuff is not so good IMO and IME.

 

[Musicman20]

I wasnt questioning the volume dont worry, I was just a little shocked to find that other may have expected more. From what Ive heard from reports, it is a very loud full sounding amplifier...with plenty of heft.

As long as it has a little bit more heft than the LM3, im happy.

 

[Red Planet]

Folks there is going to be a major difference going from 8 to 4 ohm loads even using the same type cab, in all directions.

Headroom, low end, SP-L's/loudness, warmth, ooomph, grunt etc.... Should I keep going.?

I have not gigged my Liner yet but most of my gigs of late I have only used one small 8 ohm cab with my Niner and that was plenty loud. I recently played a gig where I unhooked the 15 I was using with a 2x10 because it was too boo-my.

With either an 8 ohm 2x10 Golight or an 8 ohm 1x12 Berg I'm good on wallop and kaboom. When I hook two Bergs up I'm scary good.

 

[Jim C]

Guess the key word here is "major" difference
There have been many here that say the difference in volume between a 4 ohm vs. 8 cabinet (all thing being equal) are not that great
I've never had 2 of the same cabs with different impedences so have no frame of reference

 

[KJung]

Guess the key word here is "major" difference
There have been many here that say the difference in volume between a 4 ohm vs. 8 cabinet (all thing being equal) are not that great
I've never had 2 of the same cabs with different impedences so have no frame of reference

We are talking two issues here. Going from 8 to 4ohms by adding a second 8ohm cab will typically make quite a difference, since you are adding cone area and power (typically 5db, which is HUGE). .

However, comparing two otherwise identical cabs, one in 8ohm and one in 4ohm version is a bit more complicated. If it is a relatively small cab (210 or even a lower end 212), then the cab might not be able to handle the additional power without exceeding its mechanical limits. So, in some cases, the 4ohm cab could actually sound like it has less low end and is brighter, as it reaches power compression.

In cases of two larger cabs (I've A/B'd, for example, two 410UL Series II cabs... one 8ohm and one 4ohm) they can often sound literally identical until really pushed, with the 4ohm sounding a bit louder, and less compressed when really pushed with my relatively low powered amp (Markbass LMII). With a DB750 or some other monster, you would probably not notice the difference.

So, kind of a complex issue. A large cab with good specs can really sound 'better' at 4ohms if you are using a moderate powered micro head, from example. A 112.... typically not.

That being said, as Agedhorse posted, different drivers are different drivers, and there can be some differences in otherwise identical cabs in different impedances. In comparing my 4ohm HT210s with the stock 8ohm HT210s, there was a bit of a voicing difference to my ear... a subtle amount of upper mid increase with the 4ohm and the same amp.

Hugely different sound, as posted by the OP, is kind of surprising to me, and I would guess it is power compression caused by running the powerful Streamliner 900 into a relatively small cab (if this hypothesis was true, the 4ohm version would sound tighter in the deep low end and brighter/grindier up top when pushed a bit versus the 'identical' 8ohm model). Just guessing there.

 

[Mooch]

Well I am very glad my SL600 is going to be coming my way this week. I currently run a HA3500 Hartke. I have 2 8ohm cabs. I recently replaced the 4x10 cab with 4 new 150w speakers.

I have had some issues with the Hartke head cutting out and having to pull my jack out of my bass and "pop" everything to get the amp to work becuase it cuts out and everything gets farty and distorted. While this was just a every now and then issue at practice last night the amp kept doing this.

At first I thought something may be wrong with my new speakers but upon just running my other cab(1x15) it was doing it to this cab as well.

Looks like i decided to upgrade at the exact time my other amp started to fail.

The Sl600 can't come soon enough!

 

[Tunaman]

I'm #4 on the Red Dirt Brothers list... they have 4 due to come next batch this week

I'M IN BABY!

Really nice guys there... I figured if they took my Celtics players they can take my order too.

 

[Mooch]

Also I had a question And I think this may have been covered but I want to make sure I am understanding correctly.

Last night I went to the local shop to get 2 speakon to 1/4" speaker chords. Well they only had 1 and it was 17 bucks. Well instead of buying another one online and waiting. If I just daisy chain to the second cab everything still works right? I have 2-8ohm cabs and this wont effect sound or hurt the amp by just daisy chaining will it? It still makes the 2 cabs a 4ohm load right?

 

[KJung]

RE: husky123's cabinets:

Just to make sure, I'd suggest checking the 8 ohm cabinet with a 9V battery to make sure that the drivers are wired in phase. Just briefly touch a 1/4" phone plug to the terminals and watch how the drivers respond. If both drivers go in (or out) together, then they are in phase. If one goes in while the other goes out, then one driver is wired incorrectly, which would explain the discrepancy in output.

That would result in a MASSIVE difference, and the 'out of phase' cab would sound so tinny and thin as to be unusable. However, +1, if that is what the OP is hearing, it might be a simple fix. That would be like the difference between a 2 x 15 cab and a 1 x 8 cab though.

 

[12bass]

RE: husky123's cabinets:

Just to make sure, I'd suggest checking the 8 ohm cabinet with a 9V battery to make sure that the drivers are wired in phase. Just briefly touch a 1/4" phone plug to the terminals and watch how the drivers respond. If both drivers go in (or out) together, then they are in phase. If one goes in while the other goes out, then one driver is wired incorrectly, which would explain the discrepancy in output.

To Mooch above, yes, it doesn't much matter whether you daisy-chain two 8-ohm cabinets, or run them from separate outputs. It results in 4 ohms either way, though technically, there's a little more resistance going to the furthest cabinet if you daisy-chain.

 

[12bass]

That would result in a MASSIVE difference, and the 'out of phase' cab would sound so tinny and thin as to be unusable. However, +1, if that is what the OP is hearing, it might be a simple fix. That would be like the difference between a 2 x 15 cab and a 1 x 8 cab though.

Just trying to eliminate one possibility. The differences as stated sound far more severe than one would expect if the drivers are relatively similar other than impedance. Though the effect should be noticeable, I'm not sure that breaking in the suspensions would make a huge difference either....

When I ordered my D210XST, an 8 ohm version came in by mistake. I don't recall that it sounded a whole lot different than my 4 ohm model.

 

[KJung]

Just trying to eliminate one possibility. The differences as stated sound far more severe than one would expect if the drivers are relatively similar other than impedance. Though the effect should be noticeable, I'm not sure that breaking in the suspensions would make a huge difference either....

When I ordered my D210XST, an 8 ohm version came in by mistake. I don't recall that it sounded a whole lot different than my 4 ohm model.

+1 A bit strange.

 

[MikeBass]

I ordered an Epifani 310UL a while back. One of the drivers was out of phase.
It was pretty much unusable.

 

[Chef]

Yep; and out of phase driver will really jack up your tone!

 

[husky123]

I would guess it is power compression caused by running the powerful Streamliner 900 into a relatively small cab (if this hypothesis was true, the 4ohm version would sound tighter in the deep low end and brighter/grindier up top when pushed a bit versus the 'identical' 8ohm model). Just guessing there.

Your hypothesis sounds dead on according to my ears.