Carver Digital Time Lens / Softeq question

[brjoon1021 10]

Hello all, 

 

Thank you for your help before. Still using my digital time lens standalone. I like it. 

 

I think I can get more use out of it by understanding its Equalization curve and that's where I need help. 

I want to use the parametric EQ on my streamer to reverse the DTLs Equalization for some tracks that sound a little bit flat or dark with the DTL EQ in place.  

I can't find any accurate specs about the EQ curve used in the DTL. There's an old audio Magazine review from 1985 which gives one figure and chat GPT brings back numbers less than half those in the audio Magazine review. 

Audio magazine says there is a 2.4 DB increase at 145 HZ and a 2.1 DB cut at 3.1 kilohertz

I have done several AI searches and looked all over the web myself for specs. As I mentioned, I'm finding conflicting information which might be due to a possible difference between DTL and soft EQ? I think maybe chat GPT found an obscure review of soft EQ? As its numbers are about 1 dB changes at those same frequencies. Whether that's an evolution in the circuit or I'm finding bad data I don't know

I really don't want to "use my ears" so to speak. I want to know what the actual EQ implemented by my device is and then set 10 parametric EQ settings reducing that by 10% each step to being completely flat ( Total reverse of DTL EQ). 

 

Do any of you know anything that can help me?  And that's step one... once I know what the actual EQ parameters are I have to figure out the Q factor for the parametric EQ, but I assume a pretty gentle slope would be the ticket as I believe analog circuits such as the dtl are going to be quite Broad and not a peak at the EQ points

 

 

Thanks!!!!! 

 

 

 

Edited Sunday at 09:10 PM by brjoon1021

[Kurt 2,946]

That's an interesting question.  I don't have the answer.  A long time ago I did a search for Carver patents.  I did not find one for DTL (there is one for Sonic Holography).  The literature I've read about the effect mentions increase in some mid base frequencies and decrease in some mid treble frequencies.   It also mentions an enhancement in the differentiation between L and R channels to increase stereo effect.   That may be difficult to mimic with an EQ. 

 

I don't know if this is a clue or not, but in playing around with my system, I've noticed that using DTL (with no other tone controls) sounds very similar to when I use Sonic Holography + a Gundry filter (Nelion installed in my C4000 preamp). 

[brjoon1021 10]

Thanks for responding. Surely somewhere there are numbers. I mean Carver was big on specs.... maybe somebody will have them or know where I can find them

Edited Monday at 01:25 AM by brjoon1021

[AndrewJohn 10,501]

It's going to be hard to find any documentation ..., as you already did what I would do - use some AI engines out there (way better than just using Google)...

 

I think you are going to have to reverse-engineer such data using electronics analysis instruments and such - that may or may not be at your disposal.  Here's why:

 

Every Carver Corp documentation about SoftEQ says that it is the same as DTL - just renamed.

 

I have read tech's descriptions about DTL circuitry (paraphrasing what my head retained) and that is that it varies from implementation component to component.  Why?  No one really knows, it's a mystery - and it could be due to production / cost decisions or real engineering changes from Bob or others on that side.

 

Second thing to be aware, Carver Corp., ended just as data was more and more digital..., meaning that not much was retained when the doors closed, and some have noted that dumpsters were the primary method of archival..., I've always pondered someone coming up with a hard disk with all kinds of data, engineering docs, marketing literature/art..., but alas, nope, not going to happen since the demise/end was just as "data" like we know it today, started to fill up the ether.

 

Lastly, few of the old timers are still around, or remember, if they are.  Bob is now retired, and when some have visited, it's a challenge sometimes, communicating, let alone asking about something he might remember from 1987, almost 40 years ago.  

 

The last thing I would consider is that anyone that had the curve data, would have published it by now..., the fact is that DTL is not that common except for a few fans.  I have a DTL (actually two) stand-alone units, and I'm going to gut one, and make it into something else - repurposing the chassis).   Point being that it was a standalone, then a feature in CD players, then a "new" feature in it's "SoftEQ" incarnation..., all that happened back in the mid 80's of the last century..., before the IBM PC and data started to get collected and Archived for small and medium sized businesses like Carver Corp.

 

I know that's not what you want to hear - but it's my perspective at the moment.

 

IF by chance you DO come up with an EQ curve data, we'd love for you to post it here - along with the archives so it can be preserved.

[brjoon1021 10]

https://www.gammaelectronics.xyz/audio_013-1985_carver.html

 

 

What do you folks think of this? 

Should I go by its measurements? 

I am not interested in turning it into a project so I suppose, 'yes" is the answer. It is a little distressing that there can be unit to unit variation... But I am not going to do any measurements or pay anyone to do them. 

 

Do any of you use the circuit either in acd player, standalone, etc...?  I like it! Just curious what others have found

[3M_Audio 2,046]

That's a nice find and there is certainly some data there to use for measurements.