# Hsu Research ASW-1203 Subwoofer – The Ultimate SQ + Value Package



## Buzzman (Jul 26, 2007)

*Introduction*

Hsu (pronounced “Shoe”) Research, based in Anaheim, California, is well known in home audio circles for offering tremendous subwoofer performance at rock bottom prices direct to the consumer. (www.hsuresearch.com) Dr. Per Hsu, the design genius behind the company’s products, has been creating waves for years in the home audio marketplace. Born in Singapore, he holds a PhD in Engineering from MIT. So, there is some serious brain power and technical knowledge behind this company and its products. I know firsthand the sound quality of Dr. Hsu’s products as I am the proud owner of a VTF-3 Mk. 3 subwoofer. Since 1995 Hsu Research has had a 12 inch car subwoofer in its product line. The latest version, and the one under review here, the ASW-1203 was introduced in mid-2003 and has not been modified since. Very little consumer feedback exists with regard to the ASW-1203. That means either the purchasers are so happy they are speechless, or that Hsu Research has not sold many of these subs. I suspect it’s the latter, because as we know in this hobby, silence is not golden. Given its price point of $139, the uniformly high regard for Dr. Hsu’s home subwoofers, and a 30-day satisfaction guarantee, you would think that a large number of car audio fanatics (especially those on a limited budget) would have jumped all over this sub. Think about what you could buy today for $139 brand spanking new (and without a satisfaction guarantee) and you would lose your lunch if SQ is your objective. Anything today that offers even the remotest glimpse of great sound quality, or even good sound quality, is probably twice the price (retail, that is) of the Hsu sub. 

I have been flirting long distance with the ASW-1203 for almost 3 years now. Despite my curiosity, I never purchased one till now. Why not? My principal obstacle was the enclosure size necessary for optimal performance. Dr. Hsu says his sub can work in an enclosure as small as .5 cubic feet, but overdamped bass is not my cup of tea, and all of the software modeling indicated that an enclosure of about 1.7 cubic feet was necessary for the ideally flat Qtc. of .707. I didn’t have room for such a large enclosure. For others, perhaps it was the sub’s looks that steered them away from a purchase. 

Saying this sub is not good looking might be kind. The ASW-1203 can be best described as a subwoofer that looks functional, as the attached photos demonstrate. It’s clearly not for show, as it doesn’t sport a chromed magnet structure, or even a rubber boot, nor a cool looking cone made of some exotic material. Even the logo on the dust cap is, shall we say, pedestrian. But, cosmetics aside, it looks and feels the part for which it was intended. Which leads me to a story that about sums things up. It’s crude, but it is a perfect analogy. Once upon a time there was a plain, not very attractive girl who was paid very little attention by the boys. She was always available for a date, but it was the girls with the nice skin, beautiful faces, great bodies, nice hair, etc. that got the boys’ attention. But one day some force brought this plain, not very attractive girl, and a boy (let’s call him Buzz ) together. She said, come on, take me out on a date, you might be surprised how much fun I am and how much you might like me. And, she said, if you don't like me, you don't have to spend time with me ever again, and I will even pay you back what you spend on me. Buzz said “damn, that sounds like a great deal. What do I have to lose? No one will have to know if it doesn't work out, and it won't cost me anything.” So, Buzz took the plunge. Well, he had a night he will never forget, and woke up the next morning wondering how come this plain, not so attractive girl satisfied him in ways all those pretty girls did not. He was so happy after that first night that he spent more time with that plain, not so attractive girl, and found himself thinking that he wanted to date that girl for a while. Well, in the subwoofer world, that plain, not so attractive girl is the Hsu Research ASW-1203.

The ASW-1203 features the following: 
•	Rugged butyl-rubber surround.
•	Four layer, 2.5 inch voice coil.
•	Convex dust cap.
•	Rugged steel basket.
•	Strong, progressive roll poly-cotton spider. 
•	Vented bumped back plate to prevent bottoming and improve cooling.
•	Large, double stack magnet assembly.

Specifications state an Xmax of plus or minus 18 mm, or about 1.5 inches peak to peak, with a 400 Watts RMS power handling, and a minimum amplifier RMS rating of 100 Watts. The only thing about these specs that will impress the vast majority of today’s car audio buying cognoscenti (known as the “kids”) is the Xmax rating. In today’s world of kilowatt amps and subs requiring kilowatt amplification, the ASW-1203 is downright “old school,” offering excellent efficiency, and the ability to pair it with classic AB amplification that provides outstanding SQ. The ASW-1203 is indeed promoted to be “a subwoofer geared towards sound quality as well as blasting bass.” The key published Thiele/Small parameters are as follows: Qts - .42; Qes - .45; VAS – 90 Liters/3.17 cubic feet; Fs – 25 Hz. Like most of us, I use these figures to calculate what might be the appropriate enclosure size for the sonic results I desire. I don’t have the capabilities or the knowledge to run independent technical tests. Nor do I place a great deal of stock in measurements. For me, particularly with speakers, it has always been about how they sound. So, this review is all about my subjective listening experience. 

Hsu recommends a sealed enclosure anywhere between .5 cubic feet and 1.6 cubic feet. Based on the relevant TS parameters, an enclosure of about 1.7 cubic feet will get you a Qtc. measurement of .707, the ideally flat measurement. But, as we have come to recognize in this hobby, ideally flat is not always the most satisfying sounding. I happened to be using in my car (a 2003 Mercedes S500) an enclosure with an approximate net internal volume of 1.25 cu. feet. I say approximate because I had it sized for 1.25 cu. feet, but because I lined it with Black Hole 5, which it turns out takes up about 10 % internal volume, I had to try and regain that lost volume by utilizing a Scanspeak Aperiodic Vent and filling the box with fiberglass. It's possible that the box is effectively slightly larger than 1.25 cu. ft. as the effect of the aperiodic vent and fiberglass cannot be calculated with exactness. But, this enclosure should yield a Qtc of around .79, which is within the range I have found to satisfy my preference for tight, articulate bass, yet delivering great extension and output in a car. In this sized enclosure, the ASW-1203 should have an Fb of around 47 Hz, and an F3 of 42 Hz. With cabin gain, this baby should be able get down LOW and make me wanna boogie. 

*Associated Equipment & Settings.*

Powering the ASW-1203 is my trusty DLS Ultimate A6 amplifier. It’s been in my system now for 2 years, and is both outstanding sounding and a great value. Rated at 500 Watts per channel, with a 4 Ohm load, it should be a perfect match with the ASW-1203. After installation, I played music for about 4 hours before doing some fine tuning and getting ready for some serious listening. I recognize that the sub may not be fully broken in at this time, but I was eager to give it a serious listen anyway based on what I heard out of the box (no pun intended). By the way, I settled on a low pass frequency of 45 Hz with a 24 db slope on the sub. I found that setting to offer the best blending with my Phass 8” midbasses in the front doors, and gave an outstanding sense of upfront bass. Now, for the listening results. 

*Listening Impressions *

I slipped a copy of “Buzzman’s Ultimate Bass Demo.” cd into the Clarion DRZ9255. Here are my impressions from certain tracks. 

1.	Shalamar - “Night to Remember” This old school “disco” track definitely puts the funk in your soul. It opens with a memorable guitar lick and kick drum covering several bars. I could feel the kick drum in my chest. I loved that sensation. Eighteen seconds in, the bass joins and provides the rhythm that carries this track. If you aren’t up and dancing at this point, you need to see a doctor. The Hsu sub reproduced the notes played by the bass player so distinctly you could “see” the strings vibrate as they are plucked. There is real grunt and power in the bottom end, and the bass guitar’s notes are not blurred. About 52 seconds in, the bass player puts together a run of 16th notes and each note is clearly discernible. An awesome start to the listening session.

2.	Diana Krall – “Temptation”: Just about everyone knows this track. Christian McBride’s opening introduction really sets up this song. Each note he plays is reproduced with outstanding clarity and definition. The depth and body one expects from an upright bass is there in spades. Diana’s piano has great presence and when she begins singing, her voice is properly located in front of McBride’s bass. Yet, her voice and each note from the bass are clearly distinguishable. 

3.	Al Jarreau –“Cold Duck”: Man I love this track. It’s another showcase for Christian McBride’s bass playing skills. I can clearly hear his fingers pull on the strings and I feel the vibrato. There is a lot that goes on in this song, and the bass is never lost in the mix. About 1.24 in McBride gives us a fabulous lick along with the piano and guitar, and Jarreau is working his scat magic. Yet, the bass is distinct, no blurring of notes, and the piano again has great body and presence. 

4.	Mary Stallings – “Centerpiece”: Another great track. It’s a vocal and bass duet, and Darryl Hall’s bass is precisely localized. The clarity and detail I hear is incredible. About 1.08 in Hall strikes a note that causes the body of the bass to reverberate. That I can hear it with such clarity is a testament to the resolving capabilities of the Hsu sub. The sound of the bass has the tonal quality it should have, and there is depth to every note. At 1.30 Mary begins a scat that lasts over 2 minutes and her voice is placed in front of the bass player. The bass notes can be heard clearly separate from her voice. Awesome!

5.	Stanley Clarke – “The Learning Curve”: This track really allows the Hsu sub to show its stuff. There is real power and drive in the bass here and the Hsu sub lets you feel it all. I can “see” Stanley’s fingers going up and down the fret. In the opening bars he bends some 8th notes and I can feel and see the strings vibrate. Forty-five seconds in the guitar, piano and drum join in and Stanley’s bass is clearly discernible in the mix, each note he plays is audible. I can’t stop listening to this track.

6.	Enigma – “Principles of Lust”: Another of my faves. The Hsu sub contributes so much to this track that it is reproduced with a sense of 3D realism I rarely hear. The bass is deep and powerful, yet it does not obscure the sonic tricks so prevalent here. At 2 minutes in the girl begins panting, and her breathing is so clearly rendered it is eerie. There is excellent layering on top of the bass. Then at 2.58 the heartbeat starts and it’s so realistic all I can do is shake my head.

7.	Galactic – “Baker’s Dozen”: I love this track as a test of transient response. The opening 30 seconds feature an electric bass guitar and kick drum playing at breakneck pace, and the Hsu sub renders each instrument clearly and the sense of speed is not lost. When the horns and guitar join in 30 seconds later, the bass remains clearly focused and audible in the mix. 

8.	Bela Fleck & The Flecktones – “Flight of the Cosmic Hippo”: Wow. The Hsu reproduces the notes played by Victor Wooten with such depth and precision, and without the muddiness that often mars the reproduction of this track. The sound of Wooten’s fingers moving up and down the strings is quite realistic, and at 2.25 in when he drops another octave, you just feel the power and energy of each note, and the clarity of the kick drum juxtaposed against the bass is first class. I am surprised the car didn’t move a few feet.

9.	Donald Fagen - “Morph The Cat”: Amazing! This might be the best sounding Steely Dan/Donald Fagen record, and the bass on the title track is enough to make you wet your pants. We are talking some serious, funky bass that reaches down DEEP into the lower registers. But, the notes are so clearly reproduced by the Hsu, along with the body and weight that gives this record its character. The bass is so well focused, tight and clean that other subs could take a lesson in bass reproduction here. 

10.	Oscar Peterson – “You Look Good to Me”: What a beautiful composition. In many ways, Ray Brown’s bass carries the melody, from the opening bars where he plays the bass with a bow and with such sensitivity. The tonality, presence, clarity and focus of Ray’s bass, combined with the sense of space and air around it, make it seem like it’s in the right corner of my dash. This sense of realism is enhanced by the clarity with which I can hear Ray humming along as he plays his bass. The kick drums at 2.30 in have great impact. Absolutely wonderful.

11.	Joni Mitchell – “Sex Kills”: This track, on her “Travelogue” cd is another of my faves. Joni is accompanied by a full orchestra on this recording, and the scale and power of this track can be clearly felt from the opening percussion strikes. The Hsu sub really struts its stuff here. The timpani and drums strike as an ensemble and the impact is palpable; you can feel the rumble. What a sensation as the closing timpani strike hits you in your gut. 

12. Verdi – “Requiem Dies Irae” (Boston Philharmonic Orchestra) – This recording was made in 1981 and can be found on the Hsu Test CD1. It’s a true audiophile recording, and a real test of a system’s ability to reproduce the power and the dynamics of a full orchestra. What a way to end the listening session. The timpani and double basses are the main reasons for the visceral impact this composition has. The timpani are located in the left corner of the orchestra, and when struck, the Hsu makes the mallet strikes sound like cannon shots. They are that powerful and clearly defined. The micro and macro dynamics of the orchestra are beautifully rendered. You can really feel the power of the orchestra as it builds to a full crescendo beginning at the 2 minute mark. I left the car feeling both exhilarated and as though I had been through a workout. Amazing. 

*Conclusion*

I have used many excellent subwoofers in my car. The Hertz ML3000 (Free Air Version); Pioneer T-SW12PRS; JBL WGti Mk.II and Morel Ultimo 12 have all done time in my system. Until now, the Morel Ultimo 12 was my favorite. While there are characteristics about the Morel that I like more (it resolves low level detail better, for example) the Hsu Research ASW-1203 has given me the most satisfying overall performance of them all. The ASW-1203 delivers bass with great clarity, detail and articulation. It has great transient response. It does all this without drawing attention to itself. In my system it blended so well with my front stage that there was no localization behind me, and you wouldn’t know I had a sub playing except for how deep it goes. And it does go DEEP. I had the lowpass crossover to the sub at 45 Hz and the results were spectacular. If you need to cross it higher, you will benefit from the greater output in the upper bass/midbass region. The ASW-1203 takes very little amplifier power to reproduce the lower frequencies that are responsible for that realism and visceral impact we look for in our music. Its synergy with my DLS A6 is obvious. The Morel, on the other hand, needs a lot of power to fully display its capabilities, and the DLS A6 was not getting it fully there. Thus, the visceral impact of the bass was not the same as with the Hsu. And, the Morel’s 2 Ohm impedance certainly puts more stress on the amplifier and my system. The results may well be reversed with the use of a more powerful amplifier. But, factor in the fact that the Morel is 6 times the price of the Hsu, that a true SQ amp capable of putting out 1,000 Watts at 2 Ohms will carry a big price, the case for the Hsu is that much more compelling. In any event, until that day, the subwoofer “only a mother could love” (given its cosmetics), the Hsu Research ASW-1203, will be providing sub bass in my system. It’s that good, and the value is undeniable.


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## jbowers (May 3, 2009)

Awesome review! You've convinced me to try a pair...now I just have to take a crowbar to the old wallet. 

Did you try any test tones to get a feel for the low end extension? If so, how would you describe the 20-30hz output? Does it seem flat-ish in your test configuration?


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## Buzzman (Jul 26, 2007)

jbowers said:


> Awesome review! You've convinced me to try a pair...now I just have to take a crowbar to the old wallet.
> 
> Did you try any test tones to get a feel for the low end extension? If so, how would you describe the 20-30hz output? Does it seem flat-ish in your test configuration?


No test tones used. I played a recording of Saint Saens Organ Symphony and the organ hits legitimate 16 Hz in parts. I felt it. In my car, with my install, I am very pleased with the response. Danny Biegel did an RTA measurement this past Saturday, and most people would pay to have the sub bass response curve I have without any EQing.


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## invinsible (May 4, 2009)

Awesome review. Every detail has be covered and spoken. Really amazed how well the sub is performing? 
How will this sub work in .75 cu.ft sealed box? 
Since you have used JBL GTi MKII sub could you tell me which one of these will perform better in terms of low end extension and which one would blend well with the fronts? Which would be a better pick? 

Thanks.


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## slade1274 (Mar 25, 2008)

Awesome detailed review Buzz. I'd love to give one a try if the mounting depth weren't so darn deep.


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## bertholomey (Dec 27, 2007)

Awesome review Buzz - Learned a great deal.


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## SPAZ (Jan 7, 2009)

Thanks for the excellent review. How loud can one of these get compared to the other subs you tried? I wonder if I should try one of these over a IDQ12.


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## Buzzman (Jul 26, 2007)

invinsible said:


> Awesome review. Every detail has be covered and spoken. Really amazed how well the sub is performing?
> How will this sub work in .75 cu.ft sealed box?
> Since you have used JBL GTi MKII sub could you tell me which one of these will perform better in terms of low end extension and which one would blend well with the fronts? Which would be a better pick?
> 
> Thanks.


Thanks for your compliments. 

Given the sound quality performance of Hsu's home audio subs, I am not surprised that this sub performs so well. The real surprise is that I had this level of performance at this price.

The Hsu sub will perform quite well in a .75 cubic ft. box, but you will sacrifice output in the lower frequencies. That may not be much of a problem for you depending on your car and its cabin gain. I can't predict what results you will have as I don't know you car, or your set up. Nor do I know how much bottom end you like. That said, if your amplifier puts out a legitimate 400 - 500 watts with a 4 Ohm load, if you build a well sealed box, properly dampened, and find the location in your car that gives you the best in car bass response, and you should be very happy. But only you will know and you would have to try it. And that's the beauty of the Hsu sub. You have 30 days to try it, and if you don't like it, you can send it back, with certain conditions. You can't do that with any other sub on the market that I am aware of. But, based on my experience, I doubt Hsu will see many coming back. 

The JBL WGti II is an excellent sub. It will play deep, and play with excellent articulation and clarity. The negatives for me were its mounting depth requirements and weight. It required much more work than the Hsu sub for me to get it well integrated into my front stage, but it never gave me that up front bass sensation and seamless blending to the extent that the Hsu does. The Hsu just disappears. I also found the Hsu to have a tonal balance much more to my liking, based on my ear and my view of what sounds most natural as a former musician and frequent attendee of live concerts. And, the JBL will cost at least $100 more than the Hsu, with the best deal you might find.


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## Buzzman (Jul 26, 2007)

slade1274 said:


> Awesome detailed review Buzz. I'd love to give one a try if the mounting depth weren't so darn deep.


Thanks Slade. The mounting depth is really not that deep. Assuming you use an enclosure made from 3/4 inch mdf, you only need 6 1/4 inch interior depth.


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## Buzzman (Jul 26, 2007)

bertholomey said:


> Awesome review Buzz - Learned a great deal.


Thanks Jason. By the way, I sent you a reply to your PM.


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## Buzzman (Jul 26, 2007)

SPAZ said:


> Thanks for the excellent review. How loud can one of these get compared to the other subs you tried? I wonder if I should try one of these over a IDQ12.


Oh, they will get VERY loud, if that's what you want. SPL is a byproduct of speaker efficiency, xmax and proper amplification. But, for me loudness was not the objective. The IDQ12 is another excellent sub. However, as I note in the review, the Hsu is a no lose proposition. If you buy an IDQ and decide you don't like it, what do you do? Put it up on eBay, and possibly take a loss. If you buy the Hsu, and decide you don't like it, you can return it within 30 days, subject to their guidelines. And, the IDQ costs quite a bit more than the Hsu. Assuming space is not an issue for you (the IDQ will work best in a smaller enclosure than the Hsu), to me, it's a no brainer.


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## Boostedrex (Apr 4, 2007)

Really nice review Buzz. Thanks for taking the time to type all of that out. I had never heard of Dr. Hsu prior to this.

Out of my own curiosity, would you mind bumping the LP filter up some and giving it another listen to see how it does? Possibly as high as 80-100Hz 2nd order? I would really appreciate it if you could. If not, no worries though. 

Zach


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## slade1274 (Mar 25, 2008)

Buzzman said:


> Thanks Slade. The mounting depth is really not that deep. Assuming you use an enclosure made from 3/4 inch mdf, you only need 6 1/4 inch interior depth.


Good to know... I'm running a DIYMA right now and love the transparency, but it is a bit imposing into my hatch area. I have been looking forward to the release of the SI BM for reasons related to practiality vs. true sonic performance. The HSU intrigues me as I've been running a VTF series for my home theater for quite some time and have always loved it. I had been wanting one of thier original tube enclosures since 1994, but they were no longer offered when I finally got to a place to pull the trigger on an HT subwoofer.


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## invinsible (May 4, 2009)

Buzzman said:


> Thanks for your compliments.
> 
> The Hsu sub will perform quite well in a .75 cubic ft. box, but you will sacrifice output in the lower frequencies. That may not be much of a problem for you depending on your car and its cabin gain. I can't predict what results you will have as I don't know you car, or your set up. Nor do I know how much bottom end you like.


My car is a hatchback very similar to the VW Golf/polo with 300L of boot space. I have Morel Hybrid Ovation 6 in front running in stock location and absolutely love the off-axis response it gives. Head unit am using is Clarion DXZ785. 
Yes I am looking for something that has a good bottom end, which dissappears with the fronts seamlessly. HSU mentions that it would do well in enclosure from .5 to 1.5 cu.ft, I assume something in between like .75 cu.ft would be good as since being a hatchback cabin gain should be good for that low end. For the price it surely looks impressive the way you have detailed it. 
My choice of listen is based on more like 80's Rock, retro music where all most all the songs has a good low end frequencies. Though SI BM is round the corner I guess Hsu could be a strong contender against it. 
JBL Gti I suppose has much more thick bass line which I guess wouldn't be as transparent as the Hsu, please correct me. Price is not the an issue anything within 300$ is fine, I just want something that would dig low and sound tight. 

What damping have you used for the box? and how much ? 

Thanks.


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## Buzzman (Jul 26, 2007)

invinsible said:


> My car is a hatchback very similar to the VW Golf/polo with 300L of boot space. I have Morel Hybrid Ovation 6 in front running in stock location and absolutely love the off-axis response it gives. Head unit am using is Clarion DXZ785.
> Yes I am looking for something that has a good bottom end, which dissappears with the fronts seamlessly. HSU mentions that it would do well in enclosure from .5 to 1.5 cu.ft, I assume something in between like .75 cu.ft would be good as since being a hatchback cabin gain should be good for that low end. For the price it surely looks impressive the way you have detailed it.
> My choice of listen is based on more like 80's Rock, retro music where all most all the songs has a good low end frequencies. Though SI BM is round the corner I guess Hsu could be a strong contender against it.
> JBL Gti I suppose has much more thick bass line which I guess wouldn't be as transparent as the Hsu, please correct me. Price is not the an issue anything within 300$ is fine, I just want something that would dig low and sound tight.
> ...


I think the Hsu sub in a .75 cubic foot enclosure will work very well for you. My enclosure is lined with Black Hole 5. I would not describe the JBL WGti as having a "thick" sound. It's far from thick.


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## jsun_g (Jun 12, 2008)

Nice to see the HSU subs getting some recognition on here! A friend of mine bought a HSU 12" home sub (it is top-firing in a cylinder, with the port bottom-firing) about 7 years ago and he still regards it as his best home stereo investment. Dr. Hsu actually responded in person when my friend had a technical question. HSU is definitely not new to the game, but more like an under-the-radar brand.


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## aps1ngh (Jul 31, 2009)

Thank you for the review. I have been searching for some information about the ASW 1203 for quite some time now since I am planning on putting a new system into my car in the autumn or early winter time. 

The two subwoofers that I am looking at are the HSU asw 1203 and the Polk SR124 both of which I've heard offer fantastic SQ for the money. The HSU is about half the price of the Polk which may be a determining factor for me.

But, has anyone tried the SR124 and the ASW 1203? Does anyone have some feedback as to the SQ of either sub?


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## jbowers (May 3, 2009)

aps1ngh said:


> Thank you for the review. I have been searching for some information about the ASW 1203 for quite some time now since I am planning on putting a new system into my car in the autumn or early winter time.
> 
> The two subwoofers that I am looking at are the HSU asw 1203 and the Polk SR124 both of which I've heard offer fantastic SQ for the money. The HSU is about half the price of the Polk which may be a determining factor for me.
> 
> But, has anyone tried the SR124 and the ASW 1203? Does anyone have some feedback as to the SQ of either sub?


I have used and installed the SR sub in several customer's cars during my days in mobile audio sales. I found it to be clean and relatively powerful, but it just didn't seem to have any "balls". It plays deep, but never had the fast transient response or power of my then-favorite sub, the JL W6V2. It also didn't seem too happy crossed over high, or in anything too far outside of the recommended enclosure. It's not a bad sub, but SQ wise I didn't find anything outstanding about it. 

We never had reliability issues, but then we only sold 3-4 the entire time we carried the line. We did have plenty of blown Momo subs come back, so much that we started steering people away from them and towards Alpine Type-S for lower budgeted customers. 

I'm about a week away from ordering a pair of ASWs, and hopefully within a few weeks I'll have the time to install and give some comparisons.


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## aps1ngh (Jul 31, 2009)

jbowers said:


> I have used and installed the SR sub in several customer's cars during my days in mobile audio sales. I found it to be clean and relatively powerful, but it just didn't seem to have any "balls". It plays deep, but never had the fast transient response or power of my then-favorite sub, the JL W6V2. It also didn't seem too happy crossed over high, or in anything too far outside of the recommended enclosure. It's not a bad sub, but SQ wise I didn't find anything outstanding about it.
> 
> We never had reliability issues, but then we only sold 3-4 the entire time we carried the line. We did have plenty of blown Momo subs come back, so much that we started steering people away from them and towards Alpine Type-S for lower budgeted customers.
> 
> I'm about a week away from ordering a pair of ASWs, and hopefully within a few weeks I'll have the time to install and give some comparisons.


Awesome. I'll pm/nag you in a few weeks to post a comparison.  Thanks.


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## jbowers (May 3, 2009)

aps1ngh said:


> Awesome. I'll pm/nag you in a few weeks to post a comparison.  Thanks.


Heh, if I'm still working 6 day weeks by then I can promise you there will still be a couple of unopened HSU boxes on the floor - hopefully I'll be pissing off my neighbors in new and exciting ways before then though


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## CraigE (Jun 10, 2008)

I've heard Buzzman's before and after.
I swear he has that new sub hidden somewhere up under the dash.
And that 16hz organ... WOW!.


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## whkana (Sep 23, 2008)

Would anyone know how the Hsu ASW-1203 compares to an Alpine Type-R 12" sub? It's amazing what you can find on the internet, and they'd cost about the same....


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## fredridge (Jan 17, 2007)

just picked mine up this afternoon.... re-doing again, I am hoping one will be enough


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## Buzzman (Jul 26, 2007)

fredridge said:


> just picked mine up this afternoon.... re-doing again, I am hoping one will be enough


Alright! I think you will find one to be "enough."


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## invinsible (May 4, 2009)

*Re: Hsu Research ASW-1203 Subwoofer  The Ultimate SQ + Value Package*

What's the sensitivity on these HSU subs ? 
How efficient are these and can they handle more than 400Rms?


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## Buzzman (Jul 26, 2007)

*Re: Hsu Research ASW-1203 Subwoofer  The Ultimate SQ + Value Package*



invinsible said:


> What's the sensitivity on these HSU subs ?
> How efficient are these and can they handle more than 400Rms?


Surprisingly, the rated sensitivity is not published, so I have asked for that detail. My guess, based on what I am hearing is that it will be around 90 - 92db at 2.83 Volts/1meter. But that is just a guess. Once I get something official I will post it.

Regarding power handling, I am sure it could handle more than 400 Watts RMS, particularly if you use a large enclosure. But, given how loudly it plays with very little power, I would be shocked if any reasonable person would ever require much more than 250 Watts RMS at any specific time.


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## Buzzman (Jul 26, 2007)

I was just informed that Hsu has VERY limited quantities of this sub left; about 10.  And, once these are gone, that's it.


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## slade1274 (Mar 25, 2008)

Good thing I bought one last night!


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## Buzzman (Jul 26, 2007)

slade1274 said:


> Good thing I bought one last night!


:laugh: They told me there was a recent uptick in sales. So, you are one of the lucky ones. I might just pick up another one myself.


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## whkana (Sep 23, 2008)

It's a good thing I work just down the street. Time to pay them a visit and pick one up!


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## Buzzman (Jul 26, 2007)

whkana said:


> It's a good thing I work just down the street. Time to pay them a visit and pick one up!


I would say so. That's what Fredridge did yesterday.


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## invinsible (May 4, 2009)

How do these compare to Boston Acoustics G5 in terms of Low end response ? Can any one heard both can point out some details on this ?


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## toyrunner (Sep 1, 2008)

I order one last week, I hope I get it for my new s2000 !


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## Buzzman (Jul 26, 2007)

toyrunner said:


> I order one last week, I hope I get it for my new s2000 !


Great. Let us know what you think after you get it installed.


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## snaimpally (Mar 5, 2008)

Buzz, nice review! Its always nice to find an undiscovered gem. I tried the Diyma and couldn't get it to blend at all, despite auto eq and ta and fiddling with polarity etc. I love my Morel Ultimo 12. I recently tried the Dayton 12 HO in a sealed 1.25 cu ft (gross displacement - Scosche 12" sub box) and was surprised at how close it comes to the Morel. The Dayton 12 HO is $138, almost the same price as the HSU.


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## whkana (Sep 23, 2008)

toyrunner said:


> I order one last week, I hope I get it for my new s2000 !


I do hope you get it. Because when I went to pick up mine 2 weeks ago, they had 2 left, and someone just ordered those 2.

Btw, although I asked their sales guy how big of an enclosure I should use for the sub, they recommended 1 - 1.25 cu.ft, with my 1 cu.ft, I noticed that although the output is clean, but it doesn't have as much extension as I expected, so you might need a bigger box than 1 cu.ft (gross volume). And I even stuffed fiber-fills already.


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## slade1274 (Mar 25, 2008)

It definitely needs more air. I tried it in the minimum size box and wasn't as happy as other drivers, so I'm going to go a different route as I need to keep the box volume to a minimum in my install.


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## drtool (Nov 26, 2007)

Great review:2thumbsup: Do you know if they are going to have a newer version to replace the old one?


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## snaimpally (Mar 5, 2008)

Buzz, you are an evil man.  I ordered one last night. So they still have stock. There is virtually nothing on the internet forums about these subs so I suspect they haven't sold many. The "they only have 2 left" seems a bit of a hype since I was able to order one. It may indicate 2 in the store even though they may have a warehouse full of them somewhere else.

Amazon has a Scosche 1.25 cu ft box for $30 shipped if you are interested. Sturdy box and cheaper than you can build it.


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## Buzzman (Jul 26, 2007)

slade1274 said:


> It definitely needs more air. I tried it in the minimum size box and wasn't as happy as other drivers, so I'm going to go a different route as I need to keep the box volume to a minimum in my install.


When you say the "minimum" box size, what specifically did you use? .5 cubic feet? You definitely want to be around 1.25 cubic feet or larger, and you will have have as much bottom end extension as anyone can reasonably need in a car environment. The smaller enclosure will have a much earlier rolloff, but depending on your car's cabin gain and your taste, that may not be so bad.


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## Buzzman (Jul 26, 2007)

snaimpally said:


> Buzz, nice review! Its always nice to find an undiscovered gem. I tried the Diyma and couldn't get it to blend at all, despite auto eq and ta and fiddling with polarity etc. I love my Morel Ultimo 12. I recently tried the Dayton 12 HO in a sealed 1.25 cu ft (gross displacement - Scosche 12" sub box) and was surprised at how close it comes to the Morel. The Dayton 12 HO is $138, almost the same price as the HSU.


Thanks for the props. I have never tried the Dayton product, but many on here like them. I also tried the DIYMA 12 but found I was more satisfied with other subs.


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## Buzzman (Jul 26, 2007)

drtool said:


> Great review:2thumbsup: Do you know if they are going to have a newer version to replace the old one?


As of now, it's doubtful there will be a replacement. But, I offered to be a guinea pig for a prototype should one be forthcoming.


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## Buzzman (Jul 26, 2007)

snaimpally said:


> Buzz, you are an evil man.  I ordered one last night. So they still have stock. There is virtually nothing on the internet forums about these subs so I suspect they haven't sold many. The "they only have 2 left" seems a bit of a hype since I was able to order one. It may indicate 2 in the store even though they may have a warehouse full of them somewhere else.
> 
> Amazon has a Scosche 1.25 cu ft box for $30 shipped if you are interested. Sturdy box and cheaper than you can build it.


Welcome to the Hsu family.  They really do have very limited stock. "Two" might be a little bit general, though, and they definitely don't have a "warehouse full of them."


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## Buzzman (Jul 26, 2007)

whkana said:


> I do hope you get it. Because when I went to pick up mine 2 weeks ago, they had 2 left, and someone just ordered those 2.
> 
> Btw, although I asked their sales guy how big of an enclosure I should use for the sub, they recommended 1 - 1.25 cu.ft, with my 1 cu.ft, I noticed that although the output is clean, but it doesn't have as much extension as I expected, so you might need a bigger box than 1 cu.ft (gross volume). And I even stuffed fiber-fills already.


Output is greatly influenced by the location of the sub in the vehicle. Here is some good reading on the subject: Aiming a woofer box in a car trunk - bass cancelation -


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## Buzzman (Jul 26, 2007)

Looks like they are all GONE.


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## snaimpally (Mar 5, 2008)

I'm glad I grabbed one. 

BTW the Dayton Elite home subs that Parts Express sells were designed by HSU.


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## Buzzman (Jul 26, 2007)

I continued my experimentation with the Hsu ASW-1203 as I purchased a cheap pre-fab enclosure measuring 1.5 cubic feet to try it in. I have been very curious about what effect a larger enclosure would have. Well, I was extremely pleased with the results: flatter response, deeper bass extension, greater low frequency output and no loss of articulation.  I just can’t get over how good this sub is, and its price makes it case even more compelling. Based on my experience to date I recommend 1.5 cubic feet as the target enclosure size, loosely filled with fiberglass or polyfill. I also like to use Black Hole 5 or No Rez from GR Research to line the enclosure. Note that if you use Black Hole 5 you have to increase the internal volume by about 10%. 

I also put the Morel Ultimo in the same enclosure and it too greatly benefitted. It was more dynamic and provided greater output in the lower frequencies than before. The Morel Ultimo definitely bests the Hsu in terms of clarity, detail and transient response. It is just incredible in these categories. However, with the DLS A6 driving it, it does not have the output in the lower frequencies the Hsu has. The Hsu sub, in combinatin with the DLS A6, reproduces bass notes with greater body, warmth, fullness and depth, thus giving the music a much more solid bass foundation which adds greatly to my enjoyment. We will see what happens when I have my new Celestra DA2K installed tomorrow and the Ultimo now has 1,300 watts available to it. 

To be continued.


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## Buzzman (Jul 26, 2007)

Today, my new Celestra DA2K amplifier was installed. The difference between it and the DLS A6 can be summed up in one word, astonishing. I plan to write a separate review of the Celestra amp. For purposes of this review, I offer the following: The Celestra amp retails for about 3.5x the price of the DLS, so it's in a different league price wise. Sonically, it is also in another league. The amp's power capabilities are quite impressive. It's rated at 650 Watts into 4 Ohms, 1400 Watts into 2 Ohms and 2100 Watts into 1 Ohm, and it draws massive amounts of current, so you know those numbers are not exaggerated. It grabbed the Hsu ASW-1203 not with an iron fist, but a titanium fist, and controlled the bass like nothing I had heard before. The bass was so tight, and extended so low and with such clarity, that an already great sounding sub sounded even even more impressive. I now had that magical combination of slam, coherency and detail. It was readily apparent that notes played through the DLS amp were blurred in comparison. Transient response was much improved. The Celestra's power capabilities provided great hope for my Morel Ultimo 12 which is quite the power monger. So, in went the Ultimo. I slipped in the Buzzman's Ultimate Bass Demo cd, and after playing a couple of tracks I knew I wouldn't be removing the Ultimo. Everything the Hsu sub did well, it did better. The Celestra amp provided it what it had not been getting with the DLS amp; lots of power and vicelike control of its huge voice coil. The fact that the Morel Ultimo 12 will remain in my system does not change my opinion that the Hsu ASW-1203 is the ultimate SQ/Value package. If I didn't already have the Morel Ultimo 12, I would be fully satisfied with the Hsu ASW-1203 providing the sub bass in my car.


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## snaimpally (Mar 5, 2008)

I have an ASW-1203 if anyone wants to buy one.


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## Vitty (Feb 26, 2011)

Just picked up 4 of these puppies. So far just using 2 and am absolutely loving them. They blend extremely well. Currently building a box to house all 4.


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## SQ Audi (Dec 21, 2010)

Where did you buy, cause a few weeks ago when I called HSU Research, they stated they haven't sold them for quite some time. 

If you know of another dealer, please spill the beans...


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## Vitty (Feb 26, 2011)

I bought them new/used. They had been sitting around the guys house for a while. He had put an anti-resonance material over the cones as he said they resonated too much when he had them in a super small .5 cf enclosure. While you can no longer read the HSU logo on the caps, they are in perfect shape. I can't even tell he had them hooked up as the terminals looked mint and untouched. 

Boy do they sure sound good! I am debating only using 2 of the 4 so I may have a pair for sale soon.


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## SQ Audi (Dec 21, 2010)

Vitty said:


> I bought them new/used. They had been sitting around the guys house for a while. He had put an anti-resonance material over the cones as he said they resonated too much when he had them in a super small .5 cf enclosure. While you can no longer read the HSU logo on the caps, they are in perfect shape. I can't even tell he had them hooked up as the terminals looked mint and untouched.
> 
> Boy do they sure sound good! I am debating only using 2 of the 4 so I may have a pair for sale soon.


Keep me in mind sir if you do...I would be very interested.


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## Vitty (Feb 26, 2011)

Will do for sure.


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## Buzzman (Jul 26, 2007)

Vitty said:


> Just picked up 4 of these puppies. So far just using 2 and am absolutely loving them. They blend extremely well. Currently building a box to house all 4.


Good move Vitty! I am glad you were able to track some down.


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## Buzzman (Jul 26, 2007)

SQ Stang said:


> Where did you buy, cause a few weeks ago when I called HSU Research, they stated they haven't sold them for quite some time.
> 
> If you know of another dealer, please spill the beans...


Call Hsu again. They called me last week because they found a few while doing inventory and wanted to know if I were interested.


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## Vitty (Feb 26, 2011)

Buzzman said:


> Good move Vitty! I am glad you were able to track some down.


Thanks! They sure look junky compared to most woofer designs. These are all go no show thats for sure. I'm all about the go though


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## Buzzman (Jul 26, 2007)

Vitty said:


> Thanks! They sure look junky compared to most woofer designs. These are all go no show thats for sure. I'm all about the go though


Yeah, I said as much in my review. Don't look at these, just listen to them.


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## strong*I*bumpin (Oct 3, 2005)

Like the IDQ's ,they dont look like much but can pound with the best of them


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## SQ Audi (Dec 21, 2010)

Buzzman said:


> Call Hsu again. They called me last week because they found a few while doing inventory and wanted to know if I were interested.


Thank you Buzz, I will do just that sir!


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## Patrick Bateman (Sep 11, 2006)

Some ramblings from yours truly about this woofer, and XBL^2 motors in general:

Audio Psychosis • View topic - Is XBL^2 Dead?


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## DS-21 (Apr 16, 2005)

Is the ASW-1203 an XBL^2-motor driver? It doesn't look like one to me. The top-plate looks too thin to fit a dual gap motor.

I know Hsu uses XBL^2 motors in at least two 120V models, their flagship vented 12" sub and their sealed 15" sub, though.


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## Buzzman (Jul 26, 2007)

DS-21 said:


> Is the ASW-1203 an XBL^2-motor driver? It doesn't look like one to me. The top-plate looks too thin to fit a dual gap motor.


You have a keen eye DS-21. Patrick’s observation was news to me as well so I double checked with Dr. Hsu. He confirmed that the ASW-1203 does not use an XBL^2 motor.



DS-21 said:


> I know Hsu uses XBL^2 motors in at least two 120V models, their flagship vented 12" sub and their sealed 15" sub, though.


According to Dr. Hsu the only sub he makes that uses an XBL^2 motor is the ULS-15.



cajunner said:


> this sub was likely designed before (or without) Klippel, but probably has some FEA work into it, considering that the good doctor shoe has a degree from MIT.
> 
> it would be worth a trip on the bikinpunk merry-go-round of DA and RTA to see what tricks the Hsu has going on with these seemingly rudimentary samples of the sub arts.


Mine is sitting unused in a box in my garage, so I will contact Erin about doing some testing on it.


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## Vitty (Feb 26, 2011)

I am currently setup to run 4 12" woofers in my vehicle and want something geared towards extreme SQ. With all the great things said about the Ultimo I had originally wanted 4 of them. However, powering them all at levels adequate to achieve their full potential is just not possible. My other two choices are the HSU and the Rainbow Profi. They don't require much power at all and could all be run off my Zuki small mono.

Anyone know much about the Rainbow Profi's compared to the HSU's?


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## DS-21 (Apr 16, 2005)

Buzzman said:


> You have a keen eye DS-21.


Not that keen, alas. It's pretty easy to spot a huge top plate. 



Buzzman said:


> According to Dr. Hsu the only sub he makes that uses an XBL^2 motor is the ULS-15.


Interesting. Thanks for the correction. They used to have a 12" model with an XBL^2 motor as well.










Here was the driver. Looks crude, but it was an $800 sub with a 500W amp after all.









But their current page doesn't show that sub, and from some quick googling their current top 12" driver no longer has an XBL^2 motor.


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## iroller (Dec 11, 2010)

Vitty, If you are going to sell a couple I may be interested let me no I'm in Burnsville


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## Vitty (Feb 26, 2011)

iroller you have PM


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## Vitty (Feb 26, 2011)

SQ Stang you also have PM.


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## Vitty (Feb 26, 2011)

Decided to keep all 4 of them.


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## Buzzman (Jul 26, 2007)

Vitty said:


> Decided to keep all 4 of them.


Very nice! What internal volume per sub did you end up using? What amps are those in your pic? These subs don't need much power. How about some more detailed thoughts on the sound?


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## bertholomey (Dec 27, 2007)

They appear to be zuki's.... if correct, are they the Eleets v. 2?


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## Vitty (Feb 26, 2011)

3 Zuki eleets 4 v.2's to power all my speakers
1 Zuki eleets small mono to power the 4 HSU's

Internal volume is at 1.5 cf per woofer(after accounting for driver displacement). I just finished my install this past weekend and then promptly lost my MS-8 remote. I am now stuck with music at a barely audible level until I find it or a replacement. After I get the system tuned up and do a decent amount of listening I will post up my thoughts on the subs. So far I am blown away by them. For the price of all 4 I would be hard pressed to find just a single 12" to rival their performance.


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## Dzaazter (Apr 28, 2011)

Ahhh, just got in contact with HSU research. They did find a couple during inventory. Bad thing, they only have 1 left for sale. $139 plus $30 shipping. Told me the manufacturer went out of business a year or 2 ago. They don't have another manufacturer lined up and don't have any plans to redesign the ASW-1203. The one left is the last you'll see of them anytime soon maybe ever. Well, anyone looking to sell me a pair please let me know. Unfortunately we won't get to see these for sale, especially after the great review and recommendation you gave for it.


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## Patrick Bateman (Sep 11, 2006)

Vitty said:


> I am currently setup to run 4 12" woofers in my vehicle and want something geared towards extreme SQ. With all the great things said about the Ultimo I had originally wanted 4 of them. However, powering them all at levels adequate to achieve their full potential is just not possible. My other two choices are the HSU and the Rainbow Profi. They don't require much power at all and could all be run off my Zuki small mono.
> 
> Anyone know much about the Rainbow Profi's compared to the HSU's?


Morel speakers can take some serious abuse... If I were going with Morel I would use fewer subs and gobs and gobs of power. I love it loud, but four Ultimos seems a little nutty 

Then again, if your alternator is up to the task it might be fun :O


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## Patrick Bateman (Sep 11, 2006)

DS-21 said:


> Not that keen, alas. It's pretty easy to spot a huge top plate.
> 
> 
> 
> ...


If I'm not mistaken, Creative Sound and Meniscus still have some Trio12s left. I have a Trio8 and it's a helluva nice driver. Like all XBL drivers, efficiency is a bit lower than average, so bring a big amp.


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## Buzzman (Jul 26, 2007)

Vitty said:


> 3 Zuki eleets 4 v.2's to power all my speakers
> 1 Zuki eleets small mono to power the 4 HSU's
> 
> Internal volume is at 1.5 cf per woofer(after accounting for driver displacement).


Excellent, you are close to the sweet spot. If you haven't already, loosely fill each enclosure with fiberglass so that they are fooled into responding as if they are in a larger enclosure, and they will be even happier, and so will you.



Vitty said:


> So far I am blown away by them. For the price of all 4 I would be hard pressed to find just a single 12" to rival their performance.


I guess you agree with the heading of my review.


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## Vitty (Feb 26, 2011)

I was going to do some experimenting with the fiber fill, but it sounds so dang good now. I guess that's the nice thing about fiber fill, I can remove it if I don't like it. Might give it a shot. 

I 100% agree with your heading in my thus far short, but enjoyable time with the HSU's.

4 of them really get to rockin!! I am finding rattles I never knew I had. Even with as loud as 4 get, they NEVER drown out the music even in the slightest bit. I can't say I've ever experienced that with any other woofers I have owned. There would always reach a point where the woofers would get so loud they would drown out the music. Not so with these. They disappear in the music. It feels like the kickbass drums are slamming right next to me in the front of the vehicle. To the point where I thought I better check and make sure my front door speakers weren't about to pound themselves into oblivion. They weren't, of course, the subs were just filling the whole car with sound and were not shouting out "HEY ALL THE BASS IS COMING FROM THE REAR!!".


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## FLDUBBIN (Aug 28, 2014)

I know I am exhuming this thread, but hopefully one of you that picked up this subwoofer will see it. I am looking for a mate to the ASW-1203 I already own. If you have one in good condition, please shoot me a message. Thanks.


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