My New Magnepan 1.7i's sound dull and lifeless on the top end...why?

Thank you for the responses. 
- Using an EQ does help, but introduces it's own set of undesirealbe sonic characteristics.
- I would hope my Pass Labs gear would be considered good SS...yet still unacceptable in the high frequencies, and only marginally better than the Prima Luna gear on the 1.7i's.
- I have a pair of LRS's who's high frequencies are vastly superior to the 1.7i's??
- Swapped out the AntiCables with some Canare interconnects and Mogami speaker cables...sounded worse.
- I've tried all the settings variations on the PrimaLuna's 8, 4, and 2 ohm, and high & low bias.

The funny/bonus thing is the harsh poorly recorded music sounds better than any of my reference audiophile recordings on the 1.7i's. I may keep them just for that gem of an attribute.

kingdeezie46 posts07-28-2021 6:05pmI would think there is a problem with the speakers. 9 DB down in the highs? If the LRS sounds good on the same equipment in the same room, something wrong with the 1.7s.

Agreed

andrewmg7 posts07-28-2021 5:56pmHave you tried using the stock u-shaped jumper in place of your anticables attenuator? Seems a likely culprit....

I'll try that. thx

audiokinesis2,592 posts07-28-2021 8:27pmGetting good measurements of large dipole loudspeakers is not trivial.

My point being, it is extremely unlikely that casual non-gated in-room measurements made with a spectrum analyzer are "accurate" when there is major inconsistency between far more sophisticated, industry-standard measurement techniques. This is a situation where I would say, trust your ears far more than you trust your measurements.

Duke

The ears are telling me the highs are significantly truncated, and the analyzer confirms what I'm hearing.

kingbarbuda289 posts07-28-2021 8:45pmI have a pair of 1.7is. I recommend until you are very familiar with the Maggies and sort this issue out, that you run them only on solid state equipment. I have not looked up the specs on those Pass Labs monoblocks. But I would use those and the Pass Labs solid state preamp. I would put back in the stock steel plate jumper for now. Also check the fuses to make sure they aren’t blown. Make sure all your cable connections are good ones. Play music that is well recorded. Examples would be Steely Dan Aja and Goucho. If there still is a problem call Magnepan. Normally the highs aren’t as big an issue as the lack of bass impact. When yiu get this sorted there are other modifications that would make a difference.

Yes, the Pass gear sounds better than the PrimaLuna for sure. I'm not lacking any bass. In fact the base is what i'm most impressed with. I called Magnepan this morning. Still awaiting a response. Thx.

ps576 posts
07-28-2021 6:40pmCheck the tweeter fuses?

Fuses look good.

russ691,216 posts07-29-2021 12:28pmI just wanted to add, make sure your banana plugs are not inserted too far. They can sometimes foul some wiring or reach the panel. Also take a flashlight and look at the wiring near the crossover and see if you see something disconnected. I seriously doubt both panels would be a problem but it is possible that a new guy mis-wired them.  
Apologies for the delayed response. We have a winner! Banana plugs were inserted too far. Backed them off a 1/8", and the magical highs appeared. I must say, these Maggie's deliver incredible musicality and detail. 

Thanks again for all the suggestions and the fix from russ69.