[JDUBS]

Hey Guys

So, I have QSC HPR-153i active 3-way towers.  They have incredible dynamics and measure quite flat in my room with the exception of the woofer frequencies (that driver goes from ~35hz to 600hz) where there are a few peaks and valleys I would like to address.  I don't have room for room treatments and / or adding subwoofers to smooth things out.  Would like to do that at the driver level.

BUT, I'd like to keep the mids / highs completely analog. 

So, I was thinking that the speaker amp has an output (that runs parallel with the input) that I could run into a miniDSP.  The miniDSP would then run into a stereo amp who's outputs would drive each of the woofers directly.  Bass driver frequency correction would be handled by the miniDSP and signals to the other drivers would remain unadulterated (no ADC + DAC conversion after the source).

Is that a reasonable way of thinking?

Thanks,
Jim

[youngho]

Interesting--so you're planning to unmount the panel and splice in the miniDSP downstream of the crossover and signal processing before the Class H LF amp?

https://www.qsc.com/resource-files/productresources/spk/discontinued/hpr/q_spk_hpr_series_specs.pdf

What are you using as a source?

[JDUBS]

Interesting--so you're planning to unmount the panel and splice in the miniDSP downstream of the crossover and signal processing before the Class H LF amp?

https://www.qsc.com/resource-files/productresources/spk/discontinued/hpr/q_spk_hpr_series_specs.pdf

What are you using as a source?

I was thinking of pulling out the bass driver from the cabinet (from the front) and disconnecting it from the LF portion of the amp from there.  It would be totally disconnected from the crossover in the mounted QSC amp.  I would run speaker cable from the LF driver OUT of the cabinet via one of the two front ports.  That would go to the new LF amp which would be connected to a miniDSP. 

Sources are vinyl, FLAC files, and Spotify.  I have a balanced preamp that has a USB input for all my digital stuff.

-Jim 

[G Georgopoulos]

what you need is room treatment,most peaks and dips have nothing to do with dsp treatment,there will still be there at a lesser intensity.MHO.

[JDUBS]

what you need is room treatment,most peaks and dips have nothing to do with dsp treatment,there will still be there at a lesser intensity.MHO.

Yeah, of course that would be ideal.  I just can't with my current setup. 

I know its possible to minimize the peaks and dips via DSP.  I was doing it with Audiolense for a while (on a full-range basis).

-Jim

[nickd]

I think you are on the right track however I would put the DSP in front of the amp in the low level imput. It makes improvements everywhere I'd used in moderation. I use a Lyngdorf TDAI 2170 integrated amp with room perfect DSP and I will never go back.

I have played with room treatments too. They are a tool (and a good one) but will not cure all the things a good DSP can fix. 

[JDUBS]

I think you are on the right track however I would put the DSP in front of the amp in the low level imput. It makes improvements everywhere I'd used in moderation. I use a Lyngdorf TDAI 2170 integrated amp with room perfect DSP and I will never go back.

I have played with room treatments too. They are a tool (and a good one) but will not cure all the things a good DSP can fix. 

Yep, that's the idea.  Grab it from the input signal to the QSC amp.

-Jim

[youngho]

It's very difficult to address the dips, unfortunately. It may also be worth trying to figure out how to minimize the speaker boundary interferences, which are likely to contribute to these.

[JLM]

DSP (or EQ) should be the last step in obtaining proper frequency balance, after having the right speakers, the right room, the right setup, and necessary treatments.  DSP/EQ can only be setup for a single listening location, so can be doing some weird things overall.  Yes, narrow dips can't be heard thankfully because if really deep (say 30 dB) the DSP/EQ would call for sucking 1,000 times the power in order to compensate, so use with care.

Most audiophiles lust for too much gear and so have speakers that are obviously too much for the given room.  This undoubtedly is your case as the QSC HPR-153i are intended for professional sound reinforcement applications, not home use.  They are rated 41-17,500 Hz +/- 3 dB, 134 dB at 1 meter maximum output.  At sane in-room sound pressure levels you'd be using 0.01 watts per amp, which is well out of the sweet range of a solid state amp.  This is a sledge hammer for more of a finish carpentry job.  Can you say "way overkill"?  I'd honestly dump the speakers and start over.


Last summer I bought Dynaudio BM5 Mk III, also active, but "just" 2-way monitors.  They are rated 42 - 24,000 Hz, 118 dB at 1 meter maximum output and have roll offs for use with subwoofers - frankly a much more reasonable solution for home use.  I am fortunate to have the right room (ala Cardas), the right setup (near-field - close to Cardas), treatments (although not really needed in my room/setup), and DSP (only to replace baffle step circuits that I removed from my main speakers).

[JDUBS]

DSP (or EQ) should be the last step in obtaining proper frequency balance, after having the right speakers, the right room, the right setup, and necessary treatments.  DSP/EQ can only be setup for a single listening location, so can be doing some weird things overall.  Yes, narrow dips can't be heard thankfully because if really deep (say 30 dB) the DSP/EQ would call for sucking 1,000 times the power in order to compensate, so use with care.

Most audiophiles lust for too much gear and so have speakers that are obviously too much for the given room.  This undoubtedly is your case as the QSC HPR-153i are intended for professional sound reinforcement applications, not home use.  They are rated 41-17,500 Hz +/- 3 dB, 134 dB at 1 meter maximum output.  At sane in-room sound pressure levels you'd be using 0.01 watts per amp, which is well out of the sweet range of a solid state amp.  This is a sledge hammer for more of a finish carpentry job.  Can you say "way overkill"?  I'd honestly dump the speakers and start over.


Last summer I bought Dynaudio BM5 Mk III, also active, but "just" 2-way monitors.  They are rated 42 - 24,000 Hz, 118 dB at 1 meter maximum output and have roll offs for use with subwoofers - frankly a much more reasonable solution for home use.  I am fortunate to have the right room (ala Cardas), the right setup (near-field - close to Cardas), treatments (although not really needed in my room/setup), and DSP (only to replace baffle step circuits that I removed from my main speakers).

Thanks JLM - trust me I know these are very much overkill.  I go to a lot live shows a lot and SOO many of them use QSC speakers that I figured I should try them at home.  I wanted something full-range and started looking for their 3-way models.  They're only 10db down at 36hz which is plenty low for me given that I use them 90% of the time for music. 

I REALLY like them.  Completely effortless dynamics.  Used well-below their rated maximums, those drivers' distortion levels are minuscule.   

I totally get what you're saying and have been down the powered small 2-way path before.  I just like the "bigger" sound of big speakers.  It just sounds more live to me.

RE: amplification, I've started down the path of using a different amp for the horn section.....so, just using the inbuilt amp for the bass drivers.

-Jim 

[FullRangeMan]

Yeah, of course that would be ideal.  I just can't with my current setup. 

I know its possible to minimize the peaks and dips via DSP.  I was doing it with Audiolense for a while (on a full-range basis).

-Jim

Paint or dye mate black all inside the speaker enclosure, it will reduce some treble. For up more bass use some of this blanket 10mm:

[JLM]

What exactly do you mean by "room correct" and what is your room like? 

I ask because IMO the majority of audiophiles way over invest in gear for the given room.  For your sound reinforcement speakers my idea of the perfect room would be huge (over 25,000 cubic feet - big enough to contain a small house). 

[JohnR]

There is no reason to think that a speaker is "overkill" for a given room (cost/aesthetics aside) unless you are a. allergic to EQ or b. you are physically constrained to be at a distance from the speaker where lobing issues come into play (i.e. nearfield/farfield/"driver integration").

In the end, it's all just geometry

[JLM]

There is no reason to think that a speaker is "overkill" for a given room (cost/aesthetics aside) unless you are a. allergic to EQ or b. you are physically constrained to be at a distance from the speaker where lobing issues come into play (i.e. nearfield/farfield/"driver integration").

In the end, it's all just geometry

BTW I use bass DSP (DSPeaker Anti-Mode 2.0 Dual Core) on my single driver speakers (25 - 20,000 Hz) in a Cardas Golden Cuboid shaped insulated/ man cave with a near-field setup, GIK panels, and side wall diffusion. 

More to the point, JDUB's speakers are "monsters" as applied for home use:  they are 3-ways designed for public address sound reinforcement in chapels, small gyms, and the like (thus my 25,000 cubic foot comment); active (600 watts/cabinet); and rated up to 133 dB at 1 meter.  The 15 inch woofer crosses over at 500 Hz, so yes driver integration is certainly an issue.  Jim likes the dynamics these speakers afford, which I appreciate.  I ask about the room because many listening spaces are poorly shaped and/or too small, have less than ideal furnishings/surface materials, and/or are compromised in setup/function (shared with family).  IMO it's absurd to have a say $30,000 in-room system in a small bedroom or family room where you can only really pull out the speakers and play at realistic levels (as apparently Jim likes to do) when the rest of the family is away.

[jk@home]

Hey Guys
So, I have QSC HPR-153i active 3-way towers....

Sounds like a fun experiment. I wouldn't do anything permanent until I was happy with the results. Remember that the DSP will add a touch of latency (time delay) but you may not notice it.

I understand why you want to leave the other drivers analog, due to your vinyl. Thats a pickle. I use only digital sources, so use a MiniDSP NanoDIGI, with seperate DACs, in front of a multi-channel pre.

[JDUBS]

Hey Guys

Just an update.  I picked up an ATI 602 amp for the horn section and am working with someone on building crossovers (for both the horn section and the woofer). 

I'll then experiment using an iNUKE NU3000DSP, applying dsp via it, and actively crossing to the horn section.  I'll be able to compare this to a full on passive approach.

The AVSForum guys have LOTS of info on using pro stuff at home so have been going to them for guidance.  Pro stuff has the ability to sound REALLY good and does so effortlessly at sane volume levels. 

-Jim

[TJHUB]

I've consiered doing something similar with my Salk 3-ways.  I used to run EQ'd subs driven by Behringer pro audio amps for my 2-channel system.  Now with the 3-ways, I don't run subs.  The Salks are bi-wireable, so I was going to drive the mids and tweeters with my monoblocks, and add a 3000DSP to drive the 10" bass drivers while EQ'ing them from ~20-400Hz.  Now I'm thinking I'd just add a MiniDSP in front of the monoblocks, and use them for the 10" drivers.  I'd then get a smaller 2-channel amp to drive the mids and tweeters.

At the end of the day, my bass isn't perfect frequency response wise, but it sounds close.  I only have a larger peak at 36Hz.  Other than that, my room measures amazingly good.  Not to much music really excites my bass peak to worry too much.  Still, I'm an audiophile at heart...

[JDUBS]

I've consiered doing something similar with my Salk 3-ways.  I used to run EQ'd subs driven by Behringer pro audio amps for my 2-channel system.  Now with the 3-ways, I don't run subs.  The Salks are bi-wireable, so I was going to drive the mids and tweeters with my monoblocks, and add a 3000DSP to drive the 10" bass drivers while EQ'ing them from ~20-400Hz.  Now I'm thinking I'd just add a MiniDSP in front of the monoblocks, and use them for the 10" drivers.  I'd then get a smaller 2-channel amp to drive the mids and tweeters.

At the end of the day, my bass isn't perfect frequency response wise, but it sounds close.  I only have a larger peak at 36Hz.  Other than that, my room measures amazingly good.  Not to much music really excites my bass peak to worry too much.  Still, I'm an audiophile at heart...

Honestly if I had a decent amp for the bass drivers, I would have done exactly what you say and just gotten a MiniDSP.  I needed an amp, too, so the 3000DSP kills two birds with one stone.

-Jim

[Russell Dawkins]

Paint or dye mate black all inside the speaker enclosure, it will reduce some treble.

Have you tried this and found it to work?

[FullRangeMan]

Have you tried this and found it to work?

I have used it, not paint, I used black dye for wood.
Automotive guys use black paint inside subs and midranges boxes since ever. I most surprised the HiFi speakers builders complete ignore this cheap and safe procedure. The effect resulting is treble reduction.

In other forum they strong suggest me Zobel filter