# A little bit let down



## vwdave (Jun 12, 2013)

So heres my story...I had my McIntosh MC440 bridged to run my mid/tweeter and the "sub" channels were run in stereo to my midbass drivers. I also had a Phoenix Gold ZPA0.5 running my sub.

I noticed that the fans on the Mac were not switching on. In an attempt to do the repair without down time to my system I decided to put my other ZPA0.5 in, and run my front 3-ways off their passive x-overs again. I thought that the extra power would be nice and if I liked it I would leave it that way, putting the Mac into my wifes car.

Well I did the install today. I have to say that I am a little let down by the PG. I have idolized these amps since high school (when they were still new) and i have been in search of a system where I could use them. Now that I have 2 installed, I feel like my expectations were set too high. 

From everything that I gathered these amps are great for the full frequency range. There isnt a crossover on the amp itself, and i didnt change any major settings on my MS-8. I did play with the EQ on the MS-8 to try and correct it, and it doesnt sound bad, but its not everything that I expected.

any input?

BTW heres a pic of my amps...the 2350 is sold to a friend, we just havnt done his install yet.


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## Coppertone (Oct 4, 2011)

Sorry to hear that your expectations were not met during the swap. Hopefully you will get back to where you were before and all will be well again.


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## vwdave (Jun 12, 2013)

It seems that if playing with my eq doesn't fix it then I will swap the Mac back in and sell one of my ZPAs. I still want to try and make this work.


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## shawnk (Jan 11, 2010)

Question, in case I'm not understanding this correctly:

You said *" run my front 3-ways off their passive x-overs again "*

This implies that you were using your Mac in an active system... is this true?

If so, then you're definitely not comparing apples to apples.

Not to say that the Mac isn't a good amp, but the ZPA's imo are right up there with the best


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## shawnk (Jan 11, 2010)

Just re-read the first post....

So indeed you were at least running the midbass actively...... there is the problem.... run a dedicated ZPA to the midbass and then another ZPA for the mids/highs for a fair comparison


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## SilkySlim (Oct 24, 2012)

So it sounds like to me that if you didn't rerun the auto tune on the ms8 then you are running off of an input that is crossed/over and tuned for mids and highs or for midbass. That would make a huge difference in sound as well as the individual channels not being time alined and corrected with the mc/active setup.

You have also introduced more passive power sucking vampires into you system (not that I'm against passive setups you can make one hellava passive system top to bottom). Just stating the facts. You can run just a couple amps and a well designed passive network and have a killer setup old school style but that's not what you have. When you go active with a processor like the ms8 it can require more tuning when you make a change in the active/passive setup.


Sent from my iPad using Tapatalk HD


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## vwdave (Jun 12, 2013)

shawnk said:


> Question, in case I'm not understanding this correctly:
> 
> You said *" run my front 3-ways off their passive x-overs again "*
> 
> ...





shawnk said:


> Just re-read the first post....
> 
> So indeed you were at least running the midbass actively...... there is the problem.... run a dedicated ZPA to the midbass and then another ZPA for the mids/highs for a fair comparison


Hey Shawn,
Well yes and no. At first I ran the Dyn 3-ways off their crossovers before I went active. Back then is when I had the best Midbass response. At this point my sub wasn't working but my Midbass was almost good enough to negate the need for a sub.

When I went fully active I never got it to sound right. Partially because the Dyn mids and tweeters are 8 ohms and the Mac only delivers 50 watts at 4 ohms, so who knows what I got at 8 (25 maybe). I then ran the tweeter and mid off their passive (bridging the 4 channel part of the Mac) and the Midbass active. That sounded better but not as good as originally. I expected that with more power I would get at least as good as my original configuration. Maybe I have my sub crossed over too high (70 Hz) to get the good Midbass.

Oh, and I have considered another ZPA for the Midbass. I don't want to go too crazy with the power though. I also don't want to sound stupid, but I read on here somewhere that when running on a passive, whatever power you have going in, that much comes out to each speaker, just at their specified frequencies. If this is true then I wouldn't need a separate ZPA for the Midbass drivers. That didn't sound right to me, but I couldn't prove it one way or another.



SilkySlim said:


> So it sounds like to me that if you didn't rerun the auto tune on the ms8 then you are running off of an input that is crossed/over and tuned for mids and highs or for midbass. That would make a huge difference in sound as well as the individual channels not being time alined and corrected with the mc/active setup.
> 
> You have also introduced more passive power sucking vampires into you system (not that I'm against passive setups you can make one hellava passive system top to bottom). Just stating the facts. You can run just a couple amps and a well designed passive network and have a killer setup old school style but that's not what you have. When you go active with a processor like the ms8 it can require more tuning when you make a change in the active/passive setup.
> 
> ...



Yes I redid the auto tune. I left my eq settings but I don't know of any other way to change the crossover points without doing the full auto tune. I have since played with the eq and it's better, but I am just noting that the PG requires more adjusting than the McIntosh did, at least to get it to sound how I like.

The PG seems to give more of a flat output where the Mac gave me more of a dynamic output. Of course the ZPA has no crossover and I defeated the crossover on the McIntosh.

I think I am just nitpicking, but there are people who say that all higher end amps sound similar. I would argue that not all power is created equal. Yes I can make this one sound just as good, but it takes the adjustability of he MS-8s 30 band eq and adjustable crossover settings to do it.


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## shawnk (Jan 11, 2010)

vwdave027757 said:


> Hey Shawn,
> Well yes and no. At first I ran the Dyn 3-ways off their crossovers before I went active. Back then is when I had the best Midbass response. At this point my sub wasn't working but my Midbass was almost good enough to negate the need for a sub.


How were you powering the set at this point with using the passives? ... were you bi/tri amping? Or bridging for the mids or....? It's not that I don't believe you when you say that you had the "best" midbass at this point, but there's some reason why and I can promise you it's not because of the passive xovers  



vwdave027757 said:


> When I went fully active I never got it to sound right. Partially because the Dyn mids and tweeters are 8 ohms and the Mac only delivers 50 watts at 4 ohms, so who knows what I got at 8 (25 maybe). I then ran the tweeter and mid off their passive (bridging the 4 channel part of the Mac) and the Midbass active. That sounded better but not as good as originally. I expected that with more power I would get at least as good as my original configuration. Maybe I have my sub crossed over too high (70 Hz) to get the good Midbass.


Sorry, but I'm a little confused here. First you say it sounds better, but then not :blush: 

Just my two cents, but if I were stuck with this scenario then I would bridge four of the channels for the midbass (creating two powerful channels and assuming I could bandpass the signal), then the final two channels would run the mid and tweets via passive xovers. Even at a nominal 25w per channel you can have significant output from those drivers



vwdave027757 said:


> Oh, and I have considered another ZPA for the Midbass. I don't want to go too crazy with the power though. I also don't want to sound stupid, but I read on here somewhere that when running on a passive, whatever power you have going in, that much comes out to each speaker, just at their specified frequencies. If this is true then I wouldn't need a separate ZPA for the Midbass drivers. That didn't sound right to me, but I couldn't prove it one way or another.


No worries.. don't feel "stupid" 

That statement "as it's worded" is a little off though.

For instance: if we have a mibdass/mid/tweet system with a 3way passive xover inline, and we feed the system say 100w of pink noise, not all three drivers will receive the full 100w. Typically the midbass will eat up most of the power, then the mid, then the tweet. 

Of coarse this is simplifying it quite a bit, but I'm just trying to get the point across


As a side note, please don't take my comments the wrong way. It's not that I don't believe that the Mac "could possibly" be a better sounding amp than the ZPA. It's just that there are too many variables in the way here to make a fair comparison

Too bad you weren't closer, I'd love to show you first hand how superior the "active" system can be compared to the it's counterpart


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## vwdave (Jun 12, 2013)

Thanks Shawn, and no I'm not taking it personally. I have learned that compared to most people I am a car audio God, but on this board, so many people know more and have way more experience than me. Plus, I posted this thread because I have very little experience with the ZPA (at least as far as using it), and you have like 6 of them in your current setup.

Ok, so my install in this car started with my mc440 having the 50x4 bridged, running the dyns on their passive xovers. I tried to bridge the 100x2 portion to run my sub (little did I know that I wouldn't get anything through the sub channels of the LOC that I was using.

I then added the JBL MS-8 and ran full active. So the 50x4 were set to run the mids and highs(on their own channels) and the Midbass drivers ran off the 100x2 portion. I discovered that on the 6 channels RCAs that I made one channel was not working, so my right Midbass wasn't working. That considered, my DS Midbass wasn't as strong as the previous setup.

I then decided that (using that erroneous logic) to bridge the 50x4 to 100x2 and run the tweeters and mids off the passive xovers, and keep the Midbass drivers on their own channels. His way I'm using 2 less channels of the RCAs, and it wouldn't need the bad channel. It worked, but once again, less Midbass. It was totally acceptable, but just took some adjustments of the eq on the ms-8.

Source the fans were not working on the McIntosh (and I finally got that ZPA working), I decided to swap them. Maybe temporarily or maybe permanently, depending I the outcome. In the process I put the Midbass back on the passive xovers, and am running it off 2 channels again.

I need to note, when I went active I changed how I mounted my Midbass. I got a lot of slack on here at first because at first I gutted the stock speakers and using their plastic trim as my baffles. When I went active I fabricated much more solid MDF baffles. When it didn't sound as good I did research and read about the effect of loosing the air movement off the back of the driver, so I trimmed the baffles to make room for air movement. I didn't notice an improvement. I only bring this up because it very likely could have effected my Midbass output, but it seems to have worked opposite to how I would expect.

So going back to passive xovers, in the past I always thought that they worked like this: assuming 100 watts going in, the xover splits the power in some ratio to each speaker that adds up to 100 watts (ie: 33, 33, 33). Go one step further, if the Midbass is 4 ohms and the mid and tweeter are 8, then the power works like 50 watts to the Midbass, 25 to the tweeter and 25 to the mid. This lead to an argument with someone on here saying that they work like this: assume 100 watts in, each speaker potentially gets the full power, but at different frequencies. This would work out to like 100, 50, and 50. Since these speakers are different ohms they won't all be equal, but if they were all 4 ohms they would all get 100 watts. I had never heard this before, but I couldn't find enough research to back up either view so I dropped the argument.


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## vwdave (Jun 12, 2013)

Oh, and I'm not saying that the ZPA isn't as good as the McIntosh, I think that I either did something wrong, or maybe the ZPA is more of a subwoofer amp. I've seen suggestions that they need 4-8 volts of signal strength, so my JBL MS-8 would need line drivers. Any validity?


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## shawnk (Jan 11, 2010)

vwdave said:


> Oh, and I'm not saying that the ZPA isn't as good as the McIntosh, I think that I either did something wrong, or maybe the ZPA is more of a subwoofer amp. I've seen suggestions that they need 4-8 volts of signal strength, so my JBL MS-8 would need line drivers. Any validity?


It might be a little bit, but I'll try to find some time in the next couple if days to explain it a little better..perhaps with a few pics to make it easier to understand.

As for the ZPA input...they don't need big line drivers. They can reach clipping with as low as 1.3-1.4 v (gain @ maximum)


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## vwdave (Jun 12, 2013)

So they can clip a clean signal at full gain with signal that low? Most amps will clip at full gain, that's why you use a line driver. 

I guess the line driver suggestion came in when I observed that my PPI PC275 seemed to push the xmax12 harder than my other zpa0.5 (the white one that I bought from trickyricky).


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## shawnk (Jan 11, 2010)

vwdave said:


> So they can clip a clean signal at full gain with signal that low? Most amps will clip at full gain, that's why you use a line driver.
> 
> I guess the line driver suggestion came in when I observed that my PPI PC275 seemed to push the xmax12 harder than my other zpa0.5 (the white one that I bought from trickyricky).


Yes, but "that low" of 1.3v is still quite a bit higher than most other amps. Most amps will reach clipping with as little as .2-.5v with the gains at maximum. That being said though, most head units, processors etc... can easily drive a ZPA into clipping. No need for a line driver 

Indeed a line driver will allow you to reduce the amplifier's input gain to a low (or perhaps even the lowest) setting thereby reducing the amp's noise floor that's induced into the output, but to be frank, any decent quality amplifier produced in the past 20 years should not have any appreciable (audible) noise floor at any gain setting so again... really no need for that line driver.


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## vwdave (Jun 12, 2013)

Ok, so no need for a line driver. 

I have a third ZPA on the way. I hope it's in as good a shape as I expect.

I'm thinking I can try the third one to run my Midbass.


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## vwdave (Jun 12, 2013)

Update: its all good. I reconfigured the MS-8 and it sounds really good now. I did notice some clipping and distortion at high levels but I will play with the crossover point in the transition between the midbass and the subwoofer. It was set at 80 hz and it didnt sound good. When I reconfigured it I changed it to 60 hz (to see what my midbass would sound like with less subwoofer interference). I think I will try to find something in between now, the midbass probably isnt good down to 60hz, so Ill try it at 65 or 70hz. Now its all about fine tuning.


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