Using Parametric EQ as a Poor Man's HPF?

[crazyBassClown]

Uh-huh. Now about your credentials?

I can stand on my head and drink beer.
Does it really matter though?
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Maybe he's right about shelving filters being made up as an audio thing rather than an electronics thing since in both The Art of Electronics - Wikipedia and Fritz Langford-Smith - Wikipedia, the only electronics references I have here, make no mention of shelving filters at all.
That leaves the audio use as the only one you could pull it from, so going against that use still seems incorrect to me.

Edit: Fritz et should point to Radiotron Designers handbook.

 

[crazyBassClown]

What exactly is the problem here?

A thread full of posts like the one below in response to the OP's question.

Why do you have such a problem with someone presenting the opposite opinion that yes, it would probably sound perfectly OK and have a similar speaker protecting effect by reducing low frequencies in a similar way, although not identical as we seem to have to established thoroughly.

Nope, it won't work the same way at all, and is likely to sound pretty terrible in most cases IME.

 

[DonBorelli]

A thread full of posts like the one below in response to the OP's question.

Why do you have such a problem with someone presenting the opposite opinion that yes, it would probably sound perfectly OK and have a similar speaker protecting effect by reducing low frequencies in a similar way, although not identical as we seem to have to established thoroughly.

What has ben established?

Like most folks, I have a simple 3 band EQ on my amp. How can I crank the bass and still take care of my speakers in an efficient and precise way without using HPF?

 

[PraiseBassing]

Be

...Why do you have such a problem with someone presenting the opposite opinion that yes, it would probably sound perfectly OK and have a similar speaker protecting effect by reducing low frequencies in a similar way, although not identical as we seem to have to established thoroughly.

Because using the filters like you have mentioned will leave certain subsonic/bass frequencies intact, while removing other useful frequencies.

 

[beaglesandbass]

Closing this for mod review.

 

[Chef]

People:
one can present one's point succinctly while still being polite and respectful. one can also make one's point and then move right along. failure to do so can result in disciplinary actions that will then limit your ability to engage in discussions here at all. do-opened for now.

 

[Chef]

I used to use the semi para eq on the mesa walkabout in "an hpf" sort of way, using the lowest band eq to trim around 50-80 hz.
So yes, one can use it that way and it can be helpful.
I've also used an outboard hpf, which does in fact work better as it was much more selective in it's functionality.
Whatever works for you is fine with me ;--)

 

[arbiterusa]

I will be the third SWR SM-400 owner in this post who will tell you that a HPF used with that head makes a night and day difference.

Guess I'm the fourth. Sure keeps the temperature on that amp down!

 

[Ric5]

 

[agedhorse]

Here's a little something from the electronics side of things regarding filter classifications:

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These 4 basic shapes (LP, HP, BP, BR) can be used in combination to create complex filter responses, and they can be modified to create different responses in and out of band. Gain can also be part of a filter's response, (active) filters are not always lossy (with a gain <1)

For example, a Baxandall bass-treble tone control filter can be broken down into a series of separate filters combined with gain (for the active version) that combine to form the resulting shape (which is simply a truncated variable LP and HP filter).

Shelving filters are no different than a form of low pass or high pass filter, just a term that the audio industry (in particular) chose to describe its shape. Shelving filters are a type of low pass and high pass filter, often have gain, and are often truncated.

 

[Raw N Low]

 

[alanolynn]

Hopped on TB this morning, hoping to thank some folks. Quite the bummer when it gets to the point where someone else causes me to not be able to reply on my own post.

That aside...Thanks to all you who had constructive and informative response. All of your input will prove very useful.

Take a moment for yourselves and embrace the chill. The mellow. The relaxation in knowing the world still turns and bassists still keep the band together. Regardless of the use of an HPF. lol

 

[alanolynn]

@Chef my question for you is, did you use an HPF with your Henry? If so, what frequency did you cut?

 

[crazyBassClown]

Here's a little something from the electronics side of things regarding filter classifications:

Invalid Link Removed

These 4 basic shapes (LP, HP, BP, BR) can be used in combination to create complex filter responses, and they can be modified to create different responses in and out of band. Gain can also be part of a filter's response, (active) filters are not always lossy (with a gain <1)

For example, a Baxandall bass-treble tone control filter can be broken down into a series of separate filters combined with gain (for the active version) that combine to form the resulting shape (which is simply a truncated variable LP and HP filter).

Shelving filters are no different than a form of low pass or high pass filter, just a term that the audio industry (in particular) chose to describe its shape. Shelving filters are a type of low pass and high pass filter, often have gain, and are often truncated.

I can't help but notice the article you quote makes no mention of shelving filters or filters with similar response at all. That hardly confirms they are the same thing as a HP filter. A specific filtering that provides the given response has been universally called a high pass shelving or low pass shelving to differentiate it from a typical HP or LP filter because it is a more complex thing rather than one of the 4 basic shapes.
This entire thread revolves around the fact that a typical shelving bass control "is not" anything like a hpf.
I suspect the reason shelving is only used as an audio term is because it really has minimal application in electronics at large except in the audio world. Considering this discussion is purely audio based it doesn't seem unreasonable to use their terminology.

 

[Systolic]

A hopefully realistic question: Why don't amp manufacturers have an actual HPF built in? If the technology is relatively simple, I'd assume relatively inexpensive, well known for quite quite some time, and universally praised, I would think that a basic fixed HPF would be in all amps. I'm not even suggesting a variable HPF like on the wonderful Mesa D800+, but a basic/generic baked in HPF at, say, 50Hz? When all of the audio design engineers from the all the brands are building their new amps, why WOULDN'T they just throw it in there if it sounds better and helps the amp run more efficiently? What am I missing?

Edit: The skeptic side of my thinks that HPF isn't all that it's cracked up to be.

The realistic cynic side thinks it's just a business/cost decision. They'll get more money back on their investment if they can put "BUILT IN OVERDRIVE" in the marketing rather than "CUT THAT LOW END YOU DON"T NEED."

 

[agedhorse]

I can't help but notice the article you quote makes no mention of shelving filters or filters with similar response at all. That hardly confirms they are the same thing as a HP filter. A specific filtering that provides the given response has been universally called a high pass shelving or low pass shelving to differentiate it from a typical HP or LP filter because it is a more complex thing rather than one of the 4 basic shapes.
This entire thread revolves around the fact that a typical shelving bass control "is not" anything like a hpf.
I suspect the reason shelving is only used as an audio term is because it really has minimal application in electronics at large except in the audio world. Considering this discussion is purely audio based it doesn't seem unreasonable to use their terminology.

A typical bass control is not the same as a typical HPF because even though they both fall into the same filter category (low-pass, high pass), the response it tailored for different purposes. One uses a truncated response and is first order, the other is not truncated and is usually between 3rd and 4th order (depending on what the designer's intent is, some also use 6th and 8th order, but not usually for bass amps).

 

[kesslari]

A hopefully realistic question: Why don't amp manufacturers have an actual HPF built in? If the technology is relatively simple, I'd assume relatively inexpensive, well known for quite quite some time, and universally praised, I would think that a basic fixed HPF would be in all amps. I'm not even suggesting a variable HPF like on the wonderful Mesa D800+, but a basic/generic baked in HPF at, say, 50Hz? When all of the audio design engineers from the all the brands are building their new amps, why WOULDN'T they just throw it in there if it sounds better and helps the amp run more efficiently? What am I missing?

Edit: The skeptic side of my thinks that HPF isn't all that it's cracked up to be.

The realistic cynic side thinks it's just a business/cost decision. They'll get more money back on their investment if they can put "BUILT IN OVERDRIVE" in the marketing rather than "CUT THAT LOW END YOU DON"T NEED."

Some, like Mesa, are starting to include them.

 

[crazyBassClown]

Why don't amp manufacturers have an actual HPF built in?

From what I understand, most do. That's one of the reasons I don't think most people actually need an additional one. AH has said earlier in the thread all of his designs do.

 

[alanolynn]

Why don't amp manufacturers have an actual HPF built in?

I'm assuming the uneducated masses would be confused by the terminology. I can only imagine how many phone calls to the company there would be when people find out that it DOESN'T cut the highs.

 

[Systolic]

Some, like Mesa, are starting to include them.

Right, I called Mesa out specifically for doing just that. They went one step better (IMHO) and put a variable HPF on there, but if it's KNOWN, by all in the know, that a HPF is an across the board benefit (or at least never a detriment,) why haven't they been on everything from everyone?