Sparkos Op-amps and digital amps

[olds1959special]

Maybe I'm a bit impulsive, but I'm addicted to listening to my 2Ci's, so I went out and bought the Kenwood L-05M amps tonight. I placed them behind each speaker. Apparently they were recapped, which is great, and were used in a studio by a famous music producer! I plugged them into the bass drivers, and found they seemed even louder than my Fosi ZA3, which is supposedly 117 watts, and these are 100 watts. Since these are power amps, there's no volume control, so I maxed out the contour controls on the speakers to boost the midrange/treble as much as possible. It's sounding pretty good, but I'm having a hard time figuring out if the balance is perfect. I would have to add a passive attenuator box before the bass driver amps to bring the level down if it's really too loud. Do I need to play pink noise and test with a dB meter?

Edited May 24 by olds1959special

[olds1959special]

It's hard to explain the emotional connection that can happen with music with these speakers when they are properly amplified. I am listening with the Fosi ZA3 maxed and the contour controls maxed. I can't tell if the balance is off, so it's within range. The Kenwood L-05M amps on the bass. This has totally fixed the bass. It's not thin anymore. I haven't tried switching the bass with midrange/treble yet but I have no reason to. This is really great!

I guess having another pair of Kenwood L-05M's might be fun to try instead of the Fosi amps, but I'll probably never find a recapped pair again. I'm somewhat of a believer in using the Fosi ZA3 on the midrange / treble, despite what Richard says, at least to add a lot more power cheaply, and not end up with a terrible result.

Edited May 24 by olds1959special

[Holmz]

6 hours ago, olds1959special said:

I don't think the Vandersteen crossovers will work for me because I would be getting the subwoofer output from the back of two of the amps for left and right.

I have a couple of Hypex 500W (bridgable to 1kW) plate amps.
I think you/we could just rebuild the signal back up in the inverse of what the passive XO did to it.
I would be a few PEQs (I think)

I might try that.
I have 2 Thiel subs and 2 plate amps, and if it all goes “down the gurgler” then I’ll just sell the used gear.
Or put it in the truck as a “doof-doof” box.
The truck is so damned loud, I can hardly hear myself think, one often needs ear plugs on long hauls off-road…

Ol’ mate from up north arrives in an hour with a more kitted out version.
 

5 hours ago, olds1959special said:

https://losangeles.craigslist.org/sfv/for/d/sherman-oaks-kenwood-amps-amazing-high/7743177365.html
 

could these work for bass only? 

Personally I would not waste any time with ^those^.
I like the idea of bandpass subs, but they are about the worst in terms of group delay, and the transient response is not all that stellar either.
You most likely need a sealed for it to be musical and work with the 2Cs.
Which also means you need “some serious umph” (power). And any box buzzing or other harmonics makes the sub instantly become localizable, which means that it does not bland invisibly.
I cannot remember when I got the 2W… it was probably in the 2003-5 timeframe.

The Vandy 2W is really well integrated. Amazingly so IMO.
If you already had stuff laying around (like I do) then maybe a DIY makes sense.
But I would really be looking for a used 2W (and help someone moving up to the newer unit.)

Removing the low note are going to make the 4x amps have a much easier life as well.
Not only will they not be pushing out the current, the voltage is also lower, and a lot of the voltage is in the low freqs… So having more amps doesn’t make it any better in terms of clipping… You’ll need the HPF to get that benefit of “reduced signal level”.

[Holmz]

1 hour ago, olds1959special said:

…. Do I need to play pink noise and test with a dB meter?

 

1. Need?
2. (Or at some point) ‘should I’?

I dunno…

• They chuck each speaker in the chamber at the Hanford-HQ.
• They seem to use measurements there at the HQ, and I have read heaps about RV using scopes and other gear long before the main stream.
  • I suspect it is possible that he was onto something.

[olds1959special]

4 minutes ago, Holmz said:

1. Need?
2. (Or at some point) ‘should I’?

I dunno…

• They chuck each speaker in the chamber at the Hanford-HQ.
• They seem to use measurements there at the HQ, and I have read heaps about RV using scopes and other gear long before the main stream.
  • I suspect it is possible that he was onto something.

I just have no idea how to do this. I need to measure the power output of the bass drivers compared to the treble / midrange. I could do this with a measurement mic, but how would I know what loudness to expect the bass driver to be in relation to the others? The sound pressure level should be lower, because it's bass, right?

Edited May 24 by olds1959special

[Holmz]

2 hours ago, olds1959special said:

I just have no idea how to do this. I need to measure the power output of the bass drivers compared to the treble / midrange. I could do this with a measurement mic, but how would I know what loudness to expect the bass driver to be in relation to the others? The sound pressure level should be lower, because it's bass, right?

No… it’s more SPL.

It should be down sloping like a “Harmon house curve”.
But the room plays into to it as well… and bass gets constructive and destructive modes.

Edited May 24 by Holmz

[olds1959special]

I am returning the Fosi amps. I found four Kenwood LM-05 mono blocks (400 watts total). The sound is full, deep, and relaxed. No more thinness. The Class D amps simply did not work well with these speakers!

Edited May 26 by olds1959special

[Richard Vandersteen]

12 hours ago, olds1959special said:

I am returning the Fosi amps. I found four Kenwood LM-05 mono blocks (400 watts total). The sound is full, deep, and relaxed. No more thinness. The Class D amps simply did not work well with these speakers!

Discerning listeners would say Class D amps don't work well, especially on analog sources!  RV