Heathit AS 101: Help with tuning cabinets for deeper bass

Hi,

I acquired a pair of 101s a couple weeks ago. I have since replaced the caps and L Pads (one of which was fried). My next goal is to see what I can do to increase the lower frequency response. I am currently using a 10 inch sub to fill out the low end. I really a enjoy a thud to my low end listening and when I remove the sub I definitely find myself missing it. I have been reading what is out there on the forums (including this one) and trying to figure out how I can tune these cabinets for deeper bass. That being said, I am wondering if part of my issue is that I am not used to 2-way speakers. For the longest time I have had Klipsch Fortes in my main system, intermittently adding a subwoofer when I desired a deeper bass response. With the 101's I just feel that the low end is so absent...no thud. Not sure if the problem is with my expectations or if the frequency can be improved otherwise? I know this has been already stated in the forum but I am wondering if someone could be so kind as to break down a recommendation of tuning the cabinets for deeper bass. Currently, the horns have the stock recommended insulation on both sides as indicated in the assembly manual. That is it. Am I removing that insulation and replacing it with wood for the tuning experimentation or am I trying to tune the port below the horn? Thank you for any assistance you can provide...

Regards,

Michael

About the only thing to do is build a bigger box. You can try entering the internal dimensions in a design program and playing with porting. But I doubt it....

A sub is likely the best option.

You might try Acousta-Stuf as a fill. It doesn't absorb low frequencies as much as fiberglass, so there's an opportunity to make the cabinet "look bigger" without degrading the box Q too much. Filling with about 1lb/cu ft should make the box seem about 25% larger in volume.

Acousta-Stuf:

http://www.parts-express.com/pe/show...number=260-330

It's not cheap, but I've stuffed ported cabinets with it with excellent results. I suggest you bring all your parameters (box volume, TS parameters etc) into WinISD and play with the port length to get the best bass extension. I've modeled the fill by setting the box Q low, about 3, and got good agreement between the model and reality.

So replace all existing fiberglass fill with Acousta? So the lacking low frequency is pretty standard with this speaker? I ask because I am new to DIY audio and part of me is just making sure that these speakers are sounding as they should. After replacing caps and L pads I definitely heard a sonic improvement with the sound stage and dynamics but it did not do anything for the low end output other then sounding better integrated overall.

If an L-pad was fried, have you checked that the woofers are still Altec?

Greets!

You can’t really extend the LF for more ‘thud’, only reduce its mid-bass ‘punch’ with a lower tuning and since the vent is nothing but a large slot the horn protrudes from, there’s no convenient way to block it off and install a tube vent without dismantling the baffle and I presume the grill assembly, so about your only easy/cheap option is to damp [stuff] it even more than it already is.

Removing most of the damping to more like the way Altec damped the Valencia [its ~twin] will yield a bit more mid-bass presence, which is what most of the ‘bass’ is in a prosound app, but then the deep bass will be even more rolled off, though it may allow a lower ‘sub’ XO point to be used.

Bottom line, for more bass gain BW it needs a significantly larger cab tuned lower. That, or use EQ to reshape its frequency response with a 3-6 dB lower system efficiency as the trade-off depending on how low you want to go and how much the room affects it.

If you want it to sound as it was intended though, then the way to go is driving it with a period correct tube system that includes tone controls. This will reshape its response somewhat due to the amp’s high output impedance, flattening the response out somewhat, making both the LF and HF sound a bit more extended and the tone controls will typically have enough adjustability to flatten them out in room to as low as any vinyl recordings I’m aware of.

GM

Thank you everyone for your responses and for helping me wrap my head around this. Fpitas, yes the woofers are still Altec. Sorry but what would be the correlation of a fried l pad and whether the woofer was still altec?

I'm thinking that the problem is with my expectations for deeper bass and not the speaker itself which I'm glad to hear in the sense that it is sounding as it was intended to sound. Thanks again.

Michael

Michael,

Often something like a fried L-pad means the speaker has been abused, and the woofers may have been blown, too. Altecs are expensive, so sometimes people replace them with another (cheaper) brand. I'm glad your woofers are still Altec.

So this brings up an interesting question. How do those all-in-one little subwoofer boxes get to the specs they represent? I think even Altec made a self-contained subwoofer/amp. I have an old KLH subwoofer with a 10" driver and it definately goes lower than my A6s with (4) 16s.

Along the same lines, how do smallish full-range loudspeaker systems get to 35Hz? Are they sacrificing that wonderful Altec mid-bass, and/or effeciency, in exchange for a pretty FR graph?

Have you tried reversing the woofer wires? Just wondering because my 101's used to shake the house off the foundation. Although Mine had 604's in them. still they should knock stuff off shelves on their own. Mine had ports the size of the horn hole.

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Originally Posted by cradeldorf

Have you tried reversing the woofer wires? Just wondering because my 101's used to shake the house off the foundation. Although Mine had 604's in them. still they should knock stuff off shelves on their own.

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Mine did too. With only 15W/ch they could give CPR from 8' away.

That said, they did not produce that low 30-35Hz rumble. But they did, to use GMs terminology, punch and even thud.

It might be the amp. I'm using very low output impedance ( .4 Ohm ) tube amps, which to my limited knowledge, allows for the significant immediate current draws needed for exciting bass response. Even the 3W cathode follower that's running my BR TV now rocked the house with my Heathkits.

BTW, here is it now. Before:

http://www.hostboard.com/forums/hbmc.../2013/04/6.jpg

After this weekends efforts:

http://www.hostboard.com/forums/hbmc.../2013/04/7.jpg

Still a work in process...can you tell I'm single?

Hi Alan,

I'm beginning to think I should have taken the trip out to NJ and purchased the 101s you recently had for sale. I'm going to switch the wire leads to the woofers as suggested and see what that does. I'm driving the speakers with a heathkit 151 which typically lacks in low end punch but drove my Fortes pretty well. Let me throw something else out there, when I turn the l pads down all the way, the woofers sound pretty muffled. Is this normal?

Michael

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Originally Posted by mpent

........when I turn the l pads down all the way, the woofers sound pretty muffled. Is this normal?

Michael

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Probably not...I would listen to each woofer separately with the hf/cd's/horns disconnected and the crossovers bypassed.If there is still low volume then the woofer voice coils may be damaged.

I agree the Lpads are only to quell the higher efficiency of the horns not to do anything to the bass. Perhaps the LF and HF wires are switched..that could be a real danger to your HF phragms if they are. :/ Your best bet is to start from the inputs on the crossovers and trace out exactly whats going where just to be sure it's all kosher. It wouldn't be the first time I've heard of somebody screwing up the wiring on a heathkit design.

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Originally Posted by cradeldorf

I agree the Lpads are only to quell the higher efficiency of the horns not to do anything to the bass. Perhaps the LF and HF wires are switched..that could be a real danger to your HF phragms if they are. :/ Your best bet is to start from the inputs on the crossovers and trace out exactly whats going where just to be sure it's all kosher. It wouldn't be the first time I've heard of somebody screwing up the wiring on a heathkit design.

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Crossovers are wired correctly as per the assembly manual. I'm a little confused now. It seems as if some of the feedback in this thread points to the notion that the bass in this model is pretty weak by design but recent feedback suggests that the bass is fairly strong (shaking the house). Opposite ends of the spectrum.

Perhaps I am explaining myself wrong concerning what I am hearing from the LF.

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Opposite ends of the spectrum.

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Or simply interpretations of strong bass, and extended bass that vary from person to person as almost all aspects of sound do.

My WAG is that you are conditioned/trained to listening with a subwoofer in system, perhaps even augmenting VLF beyond a natural or intended level. I'm not aware of any vintage 2-way system designed for or capable of that type of reproduction. In a nutshell, you're hearing/judging the AS-101's with contemporary "bass heavy" pre-conceived expectations.

Just my .02...............................

I don't think most vintage systems accounted for baffle step, either.

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Originally Posted by bowtie427ss

Or simply interpretations of strong bass, and extended bass that vary from person to person as almost all aspects of sound do.

My WAG is that you are conditioned/trained to listening with a subwoofer in system, perhaps even augmenting VLF beyond a natural or intended level. I'm not aware of any vintage 2-way system designed for or capable of that type of reproduction. In a nutshell, you're hearing/judging the AS-101's with contemporary "bass heavy" pre-conceived expectations.

Just my .02...............................

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Yes!!!! I agree 100%...and this is the precise issue that I have been trying to tease out in my own head. I am a complete novice when it comes to DIY audio and this is very much a budding hobby of mine. These speakers have been my first project. My first attempt at soldering in new caps; l pads and assessing sound output etc. Frankly, I don't even know what you mean when you differentiate between strong bass and extended bass. I am trying to balance what is pleasing to my ears and whether these speakers are sounding as they were intended to sound. To further complicate things, there is this nagging part of my psyche that further complicates this endeavor by creating pause...perhaps wonder...of whether I actually wired everything in correctly considering this my first attempt and if indeed I did, then wow...I am surpirsed that you did it right on your first try. My neurosis can be good but it can also drive me nuts.

That being said what will stop this insanity is a confirmation of whether my woofers are operating properly. I suppose if they test to spec then I can rest easy knowing that these speakers are sounding as they should and I can add a sub when I feel like adding a sub to get the sound that is more pleasing to my ears. So, please, can someone recommend the best way of going about this. I have a digital multimeter.

My guess is that they are operating properly. Sans the subwoofer, I have listened to a variety of music...jazz, rock, classical from a variety of source recordings (vinyl, cd). Jazz always sounds phenomenal. Rock...depending on what I am listening to...sounds very good as well. It's just that when I add a sub I get the bass response that I enjoy and I'm struggling with that because what I am thinking is that I should be getting a very good response from a 15 inch woofer as that in the 101s. Thank you everyone for all your input.....so perhaps one last stream of assistance on testing those woofer, please....

Michael

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That being said what will stop this insanity is a confirmation of whether my woofers are operating properly. I suppose if they test to spec then I can rest easy knowing that these speakers are sounding as they should and I can add a sub when I feel like adding a sub to get the sound that is more pleasing to my ears. So, please, can someone recommend the best way of going about this. I have a digital multimeter.

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There's nothing wrong with a little faith in your ear/brain connection.;)

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Frankly, I don't even know what you mean when you differentiate between strong bass and extended bass.

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Strong bass = Michael Jackson's "Billy Jean" bass line that get's you moving and reaching for the volume knob for some clockwise rotation even if you hate the song.

Extended bass = 64 foot pedal bombard stop on a large pipe organ, T-rex walking thru the jungle on a Telarc CD, the note at the end of "Lucky Man" by Emerson Lake and Palmer, essentially the lowest musical octave on down into the subsonic realm where acoustic energy is mostly palpable and barely audible................................... 16hz.

Just an example of my interpretations...........................

Quote:

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Originally Posted by bowtie427ss

Or simply interpretations of strong bass, and extended bass that vary from person to person as almost all aspects of sound do.

My WAG is that you are conditioned/trained to listening with a subwoofer in system, perhaps even augmenting VLF beyond a natural or intended level. I'm not aware of any vintage 2-way system designed for or capable of that type of reproduction. In a nutshell, you're hearing/judging the AS-101's with contemporary "bass heavy" pre-conceived expectations.

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Agreed! I fell into the same trap. I also had (have) a 10" subwooder that I used with my crappy little satellite speakers for years. In order to get any bass whatsoever I had to turn the sub way up. Once I replaced the satellites with the Heathkits and left the sub out I felt something missing. I put the sub back in and it was back.

But a funny thing happened along the way, my musical tastes changed and expanded. Altec drivers, along with tube amplifiers, educated me to the nuance of more delicate and sophisticated music. I now enjoy more acoustic music, especially jazz. My subwoofer is startlingly out of place now. I learned I had the sub turned way up beyond the point of what would have been heard live or what the recording engineer intended. When I use it now. I keep the volume knob on 1-1/2 instead of 5 where I had it before. But to tell you the truth, it doesn't really enhance the experience. Mostly it's off.

I like the thump of good bass repsonse as much as anyone, but not at artificial levels that distort the intended musical experience. I have learned that the thump of a bass drum or the low E on a bass guitar are not located in that lower frequency spectrum. As far as I can tell, 30Hz does not thud, it rumbles. 40Hz is all I need for my listening taste and I do not want to give up that "in your chest' thumpy mid-bass for the occasional 30Hz passage.

I have also noticed that with the sub off, I can still hear very low frequencies depending on where I am in the house. The room acoustics plays a vital role in the ability to hear these very long sound waves. It is very possible that your speakers are producing them, you just can't here them because some aspect of your room is thwarting them.

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Originally Posted by mpent

so perhaps one last stream of assistance on testing those woofer, please....

Michael

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try hooking the 15 up direct and maybe swap polarity at the speaker terminals?
i'm new to messing with crossovers myself. but did you say that when you adjust the L pad the lows get mushy? that should not happen at all. i would not rule out crossed wires
i added new crossovers to my regular home speakers and the bass went from vague and passable to downright painful.

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Originally Posted by alancohen

But a funny thing happened along the way, my musical tastes changed and expanded. Altec drivers, along with tube amplifiers, educated me to the nuance of more delicate and sophisticated music. I now enjoy more acoustic music, especially jazz.

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altecs must make you old after many years of thrash/metal i find myself more and more on the elevator music station. :D
i've found it's not always the music but the spaces in beween.

Altecs certainly helped broaden my musical tastes. Certainly agree with them being particularly adept with acoustic stuff, and jazz. They've really helped turn me on to good big band/swing type stuff.

The "Chairman of the Board" comes to mind :D Count Basie "Blues in Frankie's Flat" (Frank Foster) - YouTube

Here's a pretty decent audio only version: Count Basie - Blues in Hoss' Flat - YouTube

or like when you hear wille nelson and you almost smell beer.

Yes, I agree. Low powered tube amps and horn loaded speakers are a match made in heaven for jazz and acoustics.

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Originally Posted by bowtie427ss

Altecs certainly helped broaden my musical tastes. Certainly agree with them being particularly adept with acoustic stuff, and jazz. They've really helped turn me on to good big band/swing type stuff.

The "Chairman of the Board" comes to mind :D Count Basie "Blues in Frankie's Flat" (Frank Foster) - YouTube

Here's a pretty decent audio only version: Count Basie - Blues in Hoss' Flat - YouTube

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Back at ya Sonny Stitt Quintet - The Nearness of You - YouTube

And to think I cut my pre-pubescent teeth on Uriah Heep & Deep Purple.

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Originally Posted by alancohen

Back at ya Sonny Stitt Quintet - The Nearness of You - YouTube

And to think I cut my pre-pubescent teeth on Uriah Heep & Deep Purple.

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Nice! Righteous and crisp! That's goin in my "after 8" collection.

For the working part of the day i have to keep the tempo up a bit. Big Jay McNeely and Detroit Gary Wiggins - YouTube

Big Jay McNeely and Detroit Gary Wiggins - YouTube

Your in for the ride of your life then because I can't tell you how many times mine sounded great one night and the next day...Blahhhh. It will truly drive you to insanity. BTW I also have become a jazz listener. Every Sunday Morning on WLAV. Jazz Brunch. :)