Which amps maximize the bass output from Heresy IV's

[captainbeefheart]

Damping factor is a poorly understood concept. You don't need as high a ratio as many people claim. Firstly because even if the amplifier has a ridiculously low output impedance the speaker wire and woofer low pass inductor will just bring it right back to average levels since they are in series with the driver and amplifier.  How manufacturers actually get these high DF specs is they are measuring it from within the amplifier to remove the series impedance of the speaker wire and speaker jack. The second reason is a little more complex.

 

Under-damped is when the system reaches 0 amplitude very fast but oscillates back and forth until it settles and stays at zero. This is worst case scenario which is why an adequate amount of damping is recommended. What is misunderstood is my next point.

 

Over-damped will cause the system to take longer in time to reach 0 amplitude. There is no oscillation which is good. But the motor takes longer to stop.

 

Critically-damped is the best case scenario. It reaches 0 amplitude in the fastest time possible and there is no oscillation.

 

Basically too much damping can be a bad thing, causing the time it takes for the motor to stop moving to be increased. Ideally you would like to shoot for a critically damped system.

 

Back in the old days there were more amps with "damping controls" which I thought was a great idea. It's a way for the customer to be able to dial in the fastest settle time with different loudspeakers. You hardly ever see them anymore on amps.

[Islander]

3 hours ago, captainbeefheart said:

Oh silly me I forgot an important detail.

 

I found optimal performance having the Sub-woofer high frequency roll-off point at the same frequency as the Heresy low frequency roll-off. Once you dial in where the Sub's attenuated point (depending on the slope) meets where the Heresy's attenuation point it sounds more natural.

 

 

I would differ on that point, because the published low frequency rolloff point is down 3 dB, so setting the sub at that point guarantees a dip at the handover frequency.  With La Scalas, for example, their low frequency “limit” is either 45 Hz or 51 Hz, depending on the year of the info.  In fact, however, the Scala starts to roll off at 100 Hz, so setting the subs’ hi-cut at 50 Hz or so will cause a very wide dip in the bass response.  This is why I recommend dialling in some overlap.  

 

Using published specs to set up audio gear doesn’t take into account how a particular speaker may sound in a particular room, which may have little in common with the room in which the published figures were obtained.  Accordingly, for accurate and smooth bass response, a test disc and an SPL meter are necessary.  This is how Tiffiny will find out where her Heresy IVs start to roll off at the bottom end.  It will naturally be higher than the published figure, which is at the -3 dB point.  With no meter, at least 20 Hz of overlap is a useful starting point.  With the La Scalas, original and LS2, I set the subs’ hi-cut where the speaker begins to roll off, i.e., 100 Hz.  Repeated instrumented testing confirmed this setting to give the smoothest bass response, with the fewest and least objectionable dips and peaks.

 

Of course, addressing captainbeefheart, your speakers in your room may respond differently.  I can only go by what I’ve learned in my listening room, but it has been consistent and repeatable.

[HiFi Heaven]

Is there some reason why you guys won't spend $8.00 on a 1/12-octave RTA that runs on your phone,

generates sine, sweep, pink noise test frequencies?  Plug & Play.  AudioTool for Android & Apple.

[Islander]

Well, there’s a concept.  So you connect the phone to the stereo, it puts out pink noise at specified frequencies, and then the phone’s microphone picks it up and gives a readout.  Is that how it works?

[captainbeefheart]

3 hours ago, Islander said:

I would differ on that point, because the published low frequency rolloff point is down 3 dB, so setting the sub at that point guarantees a dip at the handover frequency.  With La Scalas, for example, their low frequency “limit” is either 45 Hz or 51 Hz, depending on the year of the info.  In fact, however, the Scala starts to roll off at 100 Hz, so setting the subs’ hi-cut at 50 Hz or so will cause a very wide dip in the bass response.  This is why I recommend dialling in some overlap.

 

The reasoning is because adding two speakers together with similar sound volume usually yields +3db in sound pressure. Where on the other hand if they intersect  at -3db the reduced signals sum to make it flat again. If you have to much overlap without enough attenuation you'll get a +3db boost at the crossover frequency above 0db/flat.

[captainbeefheart]

*

[Islander]

2 hours ago, captainbeefheart said:

 

The reasoning is because adding two speakers together with similar sound volume usually yields +3db in sound pressure. Where on the other hand if they intersect  at -3db the reduced signals sum to make it flat again. If you have to much overlap without enough attenuation you'll get a +3db boost at the crossover frequency above 0db/flat.

 

I see your logic, but where I differ is in the faith in the published -3 dB point.  Room gain or other effects caused by the room can cause a given speaker or pair of speakers to behave somewhat differently from the specs.  The speakers may be able to go lower than spec (a happy but rare situation) or they may not be able to reach their spec.  This is why I insist that testing is the only way to know what’s really going on in a particular room with a given pair of speakers.

 

In testing my La Scalas, the test CD produced tones from 200 Hz right down to 10 Hz in 10 Hz increments.  This allowed me to see exactly what the speakers were doing and how the sub (I started with one sub) was interacting with them.  Luckily, I had made up charts with spaces for the output at each increment, and I had printed quite a few of them, because I did very many test runs, with subtle changes in the settings of the sub and the EQ.  This was the equalizer that I no longer used in my system, because it produced a slight veiling effect that had been inaudible with 1970s electronics but was obvious with 21st century gear.  Figuring that human ears are not as discriminating in the bass range as they are in the midrange, I hooked up the 10-band equalizer, which had been sitting on the shelf.

 

Using just one channel of the EQ, it was easy to correct the one dip and the one peak that was still there after setting and resetting the subwoofer controls.  Of course, the response curve still had some curves.  It wasn’t as straight as a ruler, but using too much correction can introduce other issues, like overdriving the sub’s amplifier if too much boost is dialled in.

 

Later, when I got a much newer sub, and later got a second matching sub, I found the equalizer to be redundant, because the new subs can EQ themselves, using test tones that they generate, and the Perfect Bass Kit, which includes a tripod, a calibrated microphone, and a length of USB cable, which runs between a socket on the back of the sub and your laptop.  After testing the sub’s output at 5 locations, the free app shows the response curve as found, and then produces the mirror image of that curve, resulting in a response curve that does come close to being ruler-straight.  The difference was immediately audible.

 

Now do you see my logic?

[captainbeefheart]

5 hours ago, Islander said:

I see your logic, but where I differ is in the faith in the published -3 dB point.

 

I never said to go off the published -3db and understand what you are saying. I agree one will need to experiment to find these spots.

 

I was only trying to give a basic concept of where to have them overlap is all. I didn't mention published specs or specifics for a reason. It's good you went into detail to deter people from going by a published spec. I only wanted to say you want them to overlap in the region where they both are roughly -3db down because the two sound sources will sum which might not occur to some people and they may aim for having them overlap too much or too little.

 

Thank you for adding what you did, it will help people better understand room interactions and help them in the efforts to blend the two together better as you cannot just go by published data for the speaker. It's possible some simple apps on peoples phones can help find these spots where their loudspeaker -3db point is in room. The Sub is obviously adjustable and can be set wherever so one only needs to find data for their loudspeaker, in this case the Heresy.

[Deang]

Real audiophiles buy their amps by the pound, lol.

[Buddy Shagmore]

Lokius for the assist!

[KT88]

Thanks Buddy Shagmore for the tip. Well, I found two stimulating discussion pages about the Lokius. One is Amir's site ASR and then also head-fi.org.

https://www.head-fi.org/threads/schiit-lokius-impressions-reviews.958856/

 

It is very funny that suddenly there "may" be lively interest again after it was frowned upon and deadly sin for 40 years to be allowed to use a nice tone control!. Amir is, as always, a bit strict with his test, but the posts show that the Lokius hits a need in a nice way.

https://www.audiosciencereview.com/forum/index.php?threads/schiit-lokius-review-equalizer.27334/

One poster writes very aptly that the Lokius is a somewhat extended tone control and has nothing to do with the requirements of an equalizer, which is also how McIntosh markets its newer Integrated hybrid amps...as an extended tone control over a handful of frequency points. And from that point of view, the Lokius is really an ok device in my opinion.
BTW it is really analogue, which should please many friends of a real analogue chain.
Haha...maybe the first scam will come soon in the future, like with Mobile Fidelity🙄, an "analogue like" digital EQ, because it is cheaper to make?

 

By the way, a very different problem for me would be solved for which I had a thread: how do I get elegantly and correctly from XLR only outputs to RCA inputs of my vintage Quad transistor amps? Now I have one possible answer, Schiit Lokius using as a XLR RCA adapter without nasty „work arounds“, in both directions workable.

[Les Lammers]

On 8/31/2022 at 5:10 PM, Tiffiny said:

Thank you for the comprehensive information. This may sound as though I am greedy but with my sub turned on, I am really pleased. It is just if I turn the sub off, I feel like the heresy could do better, and my 50 watt amp is likely under powering..?? That being said, I would like to find the most synergistic upgrade for amplification. I did do the room crawl. As far as getting the phase right, I did it alone over the course of a few months LOL, a lot of trial and error but currently with the sub on, my set-up sounds fairly well blended on most music. The sub does not draw attention to itself on most music. The minute I turn the sub off, it is like what happened... Even the mids get thin.

 I have a room from audio hell. This may sound like heresy, but I think I will add a Schiit Loki Max to the rig.

 

ttps://www.ecoustics.com/products/schiit-audio-loki-max-eq/

[Buddy Shagmore]

I added the Lokius to my gear a few months ago, and am now wondering why the heck didn't I do that sooner?

My Chorus II's have never sounded better, with an enhanced low end, if desired, that was missing before. That plus fine tuning the mids and highs is just the ticket. The XLRs give you some brag swag. Plus it's silver! 👊

[Islander]

9 hours ago, KT88 said:

 

By the way, a very different problem for me would be solved for which I had a thread: how do I get elegantly and correctly from XLR only outputs to RCA inputs of my vintage Quad transistor amps? Now I have one possible answer, Schiit Lokius using as a XLR RCA adapter without nasty „work arounds“, in both directions workable.

 

I had a similar problem when I introduced the XLR-only E-V Dx38 into my system.  For years, I used RCA-to-XLR cables, but it always seemed like the dodgy way to go, with no level correction.  Finally, here on the Forum, I read about the ART CLEANBox Pro.  It’s a small metal box with 4 channels running through it.  You can go from stereo RCA in the front to XLR out the back, or from stereo XLR in the front to RCA out the back.  It’s not just a connection adapter, it also converts consumer-level input signals to pro line-level signals.  The device costs only about $90, and adds no noise at all.  It may actually reduce noise.  It’s powered by a small wall wart, and can be located out of sight and left On continuously if you like.  The CLEANBox also has two level knobs, so you can set its output to suit your setup.  Highly recommended.

 

My Cleanbox came from Long & Mcquade, a musical instrument and stage/DJ supply shop.  In the US, Guitar Center likely carries them, or you can order one online.  ART is the company name, and they make a variety of similar problem solvers.