What is the exact difference between the envelope and the email in smtp?Why does the protocol need the envelope? In snail mail, the letter needs not contain addresses and is not visible to the postman (at least that's what you want to believe), so all the routing is made entirely based on the envelope and that is clear to me.However in e-mail, the letter itself is parseable and has headers such as From: and To. Why is that not enough to route email? Why do we need an envelope?And what is the meaning of a divergence between the envelope and the email itself?
Does it necessarily mean that someone is trying to game the system, or is it, under certain circumstances (what circumstances?), legal to have a difference between them.Your clarifications are more than welcome.Puzzled email receiver. The recipient address in the SMTP RCPT TO: command is what mail transports use to determine the actual recipient of an email. The addresses in the To: and Cc: headers are there for mail readers to display to users who the recipients are, but they're not actually used by mail transports.Most mail clients set the same addresses in SMTP RCPT TO: and MAIL FROM: commands that they insert in To:, Cc:, and From: headers, so the 'envelope' addresses will be the same as the addresses in the headers.Envelope and header addresses will usually agree for most legitimate mail. Notable exceptions are Bcc: addresses and mailing lists.Spammers often forge header addresses to try to avoid spam filters.
The bottom line is that the overhead would be too great. When mail servers are processing millions of messages per day, it's much faster during the SMTP session (The Envelope) when the mail server can process individual commands.If you didn't use an Envelope, you would have to push the entire message at the SMTP server, before you could find out if the message needs to be rejected.
- 70's MXR envelope filter-perfect garcia like tone,the easiest to dial in and it sounds killer before a tubescreamer,distortion + or ds-1.opens and closes evenly and with great touch sensitivity on all strings and every position on the neck. Keeps your guitars tone in tact.
- The Basics of Synth Envelope Parameters, Functions and Uses. Envelopes can be used in synthesis to modulate literally anything in the signal path including the parameters of other modulators like LFOs. Yet many still consider their use simply in terms of amplitude modulation alone. Before getting into alternate uses.
Envelope Pedal
Some messages are quite large (I've seen 100+Meg messages working with GIS images).By using an Envelope, we can issue specific 1 line commands against the mail server, and the mail server will tell us if we are successful or not, right then and there. The envelope is used by the SMTP server and the message headers are used by a mail reader as everyone else has said.What has not been said is that the RCPT TO: is used to route the message to a specific user regardless of where the user's name appears in the headers. The user does not necessarily need to appear in the To: or even the Cc: headers.
Envelope detectors are often a component of other circuits, such as a compressor or an auto-wah or envelope-followed filter. In these circuits, the envelope follower is part of what is known as the 'side chain', a circuit which describes some characteristic of the input, in this case its volume.
Think of a Bcc: where the only thing that the receiver knows is who the message was from. In this case, the To: and CC: headers should be empty - hence the blind part of BCC. In another case, if an email message has the user mentioned in the CC list along with 10 other users, how can the SMTP routing pick the appropriate user. The answer is that it uses the RCPT line to route the message.This is also used when routing via mailing lists. The To: header will contain the mailing list e-mail address. An SMTP system will generate separate messages for each user in the list each with a specific RCPT TO: user@host.
Wah Vs Envelope Filter
In this case, the user's name will not even appear in any of the other headers.
Yep, autowahs are modulated by an LFO- ie sweeps like a regular phaser of flanger. Envelope filters are filters modulated by an envelope created by your playing dynamics, and sculpted with the onboard controls.
Best Envelope Filter Pedal
Envelope modulation can be applied to other effects, ie Polyphase and EP-1 which have LFO and Envelope phasing modes.The main difference between something like the Mad Professor and Prometheus VS Maxon AF-9 is that the MP and Prometheus are ota filters, and the Maxon is an optical filter. Ota filters are often found in synths, have faster envelope response, and a whispier/paper sound(still fat), for lack of a better term.
Spacier sounding. Optical filters like the Mutron/Qtron/Meatball/AF-9 etc respond a little slower, are gurglier and funkier, etc.