# Bag End ID-18 Pro Subwoofer Discussion Thread



## theJman (Mar 3, 2012)

*Bag End ID18-Pro​**By Jim Wilson (theJman)*

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Start with a fairly generic nondescript cabinet covered in truck bedliner, add what appears to be a PA speaker and couple that to an amp with a relatively low power rating and what do you get? Under most circumstances it would be something laughable, but in the case of the Bag End ID-18 Pro you get astonishing results. This company's approach to subwoofers is unconventional -- by typical home theater standards anyway -- but what they ultimately achieve sound quality wise is unbelievable. The price is a bit too rich for my wallet, but oh how I enjoyed hearing the ID-18 Pro with my own ears. This is reference quality bass, plain and simple. You're going to need at least a pair of them, but what you'll end up with is a system that is rivaled by few others. I now understand why movie studios use Bag End subwoofers to mix their soundtracks. I'm smitten.

*For the full review Click Here​*​


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## Todd Anderson (Jul 24, 2009)

Great read, Jim! This is sub is from a company that hasn't been on my radar (and definitely not one that comes up time (and time again) on forums. The mere fact that it revealed imperfections is amazing in itself...


Question for you: In terms of the limiter... would it kick in under what you would consider normal levels of use? Or only when you were pushing the sub overly hard?


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## Picture_Shooter (Dec 23, 2007)

Well , is well. I personally would never get this sub even for $1k! If I was to get an 18" and I had a budget of $2k my simple choice would be the Seaton! Thanks Jim for the review and time you put into it. Its cool that you find subs like this that we normally would have never heard or found until you posted it. 

How would you rate this sub to PSA 15" or HSU 15" or Rythmik 15" subs? I would say these three would be a much better buy.

Last are you sure the brand is called "Bag End" and not "Dead End"? (ok bad joke).


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## theJman (Mar 3, 2012)

Todd Anderson said:


> Question for you: In terms of the limiter... would it kick in under what you would consider normal levels of use? Or only when you were pushing the sub overly hard?


Normal level, but it's funny you should ask that question... as mentioned in the review this one was a well-used demo unit, and it may turn out that it had a problem. Since the review was published I've been conversing with my contact at Bag End -- who happens to be the chief engineer -- and he's telling me the limiter should not make a sound like I was hearing. It's designed to "softly" attenuate anything that might prove difficult for the sub to reproduce, without any loud sounds. And if I understand him correctly it's actually tunable, not fixed, so it may be out of adjustment (for lack of a better term). There may be more to follow on this topic.


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## theJman (Mar 3, 2012)

Picture_Shooter said:


> Well , is well. I personally would never get this sub even for $1k! If I was to get an 18" and I had a budget of $2k my simple choice would be the Seaton! Thanks Jim for the review and time you put into it. Its cool that you find subs like this that we normally would have never heard or found until you posted it.
> 
> How would you rate this sub to PSA 15" or HSU 15" or Rythmik 15" subs? I would say these three would be a much better buy.
> 
> Last are you sure the brand is called "Bag End" and not "Dead End"? (ok bad joke).


I absolutely love to review products from small companies, ones that few people know of or folks who aren't afraid to think outside the box (literally and figuratively, and that was a good joke ). A bunch of the subwoofers I've written about fall into one of those categories, and I couldn't be happier about it.

Bag End is definitely not a company who caters to the "bench racer", so they aren't for everyone. First and foremost, they are about precision; dynamics and transient response are _everything_ to these people, and in that conviction they are unwavering. That instantly made us kindred spirits. I wish they made something like a dual-opposed with 15" drivers - retain the phenomenal sound, but with a bit more output. I would scrape together my pennies in order to be the first person to buy one of those.

BTW; Mark doesn't currently make an 18" subwoofer. Were you thinking of JTR by chance?


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## Todd Anderson (Jul 24, 2009)

theJman said:


> Normal level, but it's funny you should ask that question... as mentioned in the review this one was a well-used demo unit, and it may turn out that it had a problem. Since the review was published I've been conversing with my contact at Bag End -- who happens to be the chief engineer -- and he's telling me the limiter should not make a sound like I was hearing. It's designed to "softly" attenuate anything that might prove difficult for the sub to reproduce, without any loud sounds. And if I understand him correctly it's actually tunable, not fixed, so it may be out of adjustment (for lack of a better term). There may be more to follow on this topic.


That's interesting... do you still have the unit? If not, I wonder if they'd send you another unit... one would have to assume they'd be motivated.


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## Todd Anderson (Jul 24, 2009)

theJman said:


> I wish they made something like a dual-opposed with 15" drivers - retain the phenomenal sound, but with a bit more output.


:T


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## theJman (Mar 3, 2012)

Todd Anderson said:


> That's interesting... do you still have the unit? If not, I wonder if they'd send you another unit... one would have to assume they'd be motivated.


I do indeed still have it, but at this point I'm not sure how they want to proceed.

During one of our exchanges he did mention that custom finishes and cabinet alterations are available, so they're writing up something I'll post as an update. After I published my review I did look around to see if I could find any others. There were a few of them, mostly years old, but none mentioned the finishes and custom enclosures. I wonder if that's something relatively new.


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## vann_d (Apr 7, 2009)

Nice review. The product obviously does not cater to the average HT enthusiast. That said, neither do many high-end offerings of any type. I could see 8 of these providing an excellent experience for one who wanted maximum precision and high output. Of course there are other ways to do that as well...


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## Almadacr (May 5, 2011)

Great review Jim , thank you :T


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## troystg (Nov 14, 2013)

The technology Bag End uses was derived from Mr. Eraths patent. Mr. Erath sold the LWE A1 speakers using that in the 60's. Sadly Mr. Erath has passed however I was fortunate enough to meet him through Mr. Gerald and had the great fortune to purchase one of his later woofer systems, a car unit and the last "latest generation" unit he built before he passed.

If the Bag End is anywhere near as good as the technology Mr. Erath developed then it will be outstandingly accurate and musical.

Troy


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## BillPetrie (Jan 26, 2013)

Hi there!
Two 18 inch subwoofers might seem over the top, but it's worth remembering that we need at least 103dB at 16Hz to get properly reproduced Home Theatre sound. That means A LOT of air has to be moved. I'm using two Peavey 18 inch Low Riders in a 20 cu ft. enclosure, fed by a rhythmic audio 400 watt amp, plus a Linkwitz transform circuit to give a Qts of 0.6 at 12Hz. They sound fantastic, but it looks like they don't go as low as the Bag Ends...Hmm.


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## schlager (Nov 9, 2010)

It looks like a standard Eminence driver. And EQ can easily be done by a cheap Minidsp or Behringer. My point is that Bag End didn´t invented the wheel and 2000 $ seems pricy. And because of all the EQ it runs out of steem quickly. Solution DIY and give it PWM 1000+ watt...:sn:

Regards Sebastian


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## troystg (Nov 14, 2013)

schlager said:


> It looks like a standard Eminence driver. And EQ can easily be done by a cheap Minidsp or Behringer. My point is that Bag End didn´t invented the wheel and 2000 $ seems pricy. And because of all the EQ it runs out of steem quickly. Solution DIY and give it PWM 1000+ watt...:sn:
> 
> Regards Sebastian


If it does follow Mr Eraths' design there is more to it than EQ or Linkwitz transform.

Troy


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## schlager (Nov 9, 2010)

troystg said:


> If it does follow Mr Eraths' design there is more to it than EQ or Linkwitz transform.
> 
> Troy


Troy, as I understand it the Bag End is just compensating the natural 12 db rolloff in sealed box below fs. I don´t see anything special in doing so, but maybe I have missed something!? The special thing may be output at 8 hz, but is there any information down there at all on films?? certainly not on any music as far as I know...


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## theJman (Mar 3, 2012)

schlager said:


> It looks like a standard Eminence driver. And EQ can easily be done by a cheap Minidsp or Behringer. My point is that Bag End didn´t invented the wheel and 2000 $ seems pricy. And because of all the EQ it runs out of steem quickly. Solution DIY and give it PWM 1000+ watt...:sn:


It's not quite that simple, as Troy has pointed out, but that's certainly part of it. Another feature of the amp -- one virtually impossible to recreate -- is the variable high pass that gradually attenuates only the portion of the signal causing the amp to clip (depicted by the red light on the RTI).

To quantify it objectively is difficult, because on paper this subwoofer really doesn't appear to offer all that much. But numbers lie here. People who buy the ID-18 are all about precision and accuracy, and that's what Bag End gives you. I wished for more output myself -- and I'm not one of those people who play at reference level -- so to an extent I understand the skepticism. But if you want some of the best, sound quality wise, this company should be on your short list.


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## BillPetrie (Jan 26, 2013)

Hi
Apparently the Bag End sub uses motional feedback on the speaker driver - this would nicely compensate for the distortion generated by the small volume enclosures on the compression-expansion cone cycles. There would still be no way to avoid the excursion limits of the speaker drivers, though. If they are Eminence units, they tend to have fairly limited excursion - hence the advice to use two of them. They definitely seem worth a look, and not unreasonably priced for the engineering involved.


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## troystg (Nov 14, 2013)

Mr. Eraths design uses a "Negative feedback comparator circuit" that corrects for any amplifier non-linearities and a notch filter to remove the box resonance. 

I don't believe the Bag End uses motional feedback since it only has one VC and no accelerator on the cone.


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## vann_d (Apr 7, 2009)

troystg said:


> Mr. Eraths design uses a "Negative feedback comparator circuit" that corrects for any amplifier non-linearities and a notch filter to remove the box resonance.
> 
> I don't believe the Bag End uses motional feedback since it only has one VC and no accelerator on the cone.


This doesn't make sense to me. When is the last time anyone saw any amplifier nonlinearites on a well built modern amplifier? Further, box resonance should be well above the pass-band of the sub if it is halfway decently constructed. No need for the filter unless the construction is cheap. On top of that, to employ the notch filter they would have to know that the resonance was negatively effecting performance and you think they would choose to implement a filter and call it a "feature" rather than fix the cause? Maybe I guess, make no sense to me...:huh:


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## Owen Bartley (Oct 18, 2006)

Jim, thank you for the review of this sub. I can still remember reading about the Infrasub 18 in an old dog-eared copy of Stereo Review, with black and white photos. This is one of the pieces of equipment that just blew me away and I read about it over and over.

It's great to see that Bag End is still making subwoofers with their own special voodoo magic, and it seems that they haven't lost their touch. I see a few comments that seem a little hard on this sub and I don't really know why. It is truly a different approach to a specific goal, being: tight, clean, articulate, and LOW bass reproduction. From a single 18" self contained unit, including amp and processing. These days it's easy for anyone to pick up a relatively affordable high excursion driver, jam it into a box or a tube, feed it from an EP4000, and achieve some very impressive output. But to some people there is more to it than just moving a lot of air, and it is a lot more difficult to achieve a more refined sound, if that is your cup of tea. As stated in Jim's review, this sub achieves that in spades, and the tradeoff is giving up some output. 

There aren't many manufacturers I can think of really creating anything significantly original or different to improve the sound in the way Bag End has... Velodyne had servo driven subs, JL's Fathom has built-in optimization, Maybe Sunfire or Ken Kriesel? I think JTR subs apply some built-in DSP, I'm not sure if the Seaton subs do. Anyway, my point is that Bag End has taken their own approach to deliver an innovative subwoofer, and we should at least appreciate that even if the specifically tailored sound isn't for you. More options = good. Innovation = good. I'll support that all day long.


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## troystg (Nov 14, 2013)

vann_d said:


> ...1)When is the last time anyone saw any amplifier nonlinearites on a well built modern amplifier?
> 2)Further, box resonance should be well above the pass-band of the sub if it is halfway decently constructed. No need for the filter unless the construction is cheap. On top of that, to employ the notch filter they would have to know that the resonance was negatively effecting performance and you think they would choose to implement a filter and call it a "feature" rather than fix the cause? ....


1) VERY true, the technology was developed when solid state was new. Now with amps such as the Hypex NCores I think the comparator circuit would actually ADD noise. That's why that portion of Mr. Eraths circuit (and if Bag End used the same) should be omitted if they used a GOOD modern amplifier. However with this circuit even a cheap amp will sound VERY GOOD and that was the point of the circuit... Not everyone is Mr. money bags and some can't afford Hypex Ncores much less for subs...

2) The design GOAL is to have a defined KNOWN box resonance so there is a known roll off below that resonance. Mr. Erath used 70Hz. He put a 15" woofer in a 1.2 cubic ft sealed box and had a FLAT, very accurate and musical response from 18Hz - 125Hz. The Bag End appears to do similar with the 18" woofer. And similarly the only drawback is quantity of output not quality. 

I used a stereo pair of 15's until I went fully active on the speakers then I switched to a stereo pair of dual 10's(similar cone area, smaller speaker profile) on the NFU system. Dual 10's in a 1.25 cubic ft sealed box flat to 20Hz works just fine to fill my smaller listening / TV room no matter what the source material throws at it. I am debating on using the old 15's in a square sealed enclosure with opposed drivers on another of Mr. Eraths units for movie playback only since the front mains are plenty for music. But that would be simply for the wow and totally ridiculous factor... :bigsmile:

Troy


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## prerich (Mar 26, 2008)

Back in the day - when I thought ultimate bass - I always thought BAG-END!!!! I've heard them but never owned them, and I've always loved them (out of my price range then). They also did a bang up job on the M-6 concentric monitor (my son has a pair finished in Mercedes Benz gloss black)!!! I think they get overlooked because they are mainly professional gear, but that paradigm is beginning to change in the HT arena!


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## vann_d (Apr 7, 2009)

troystg said:


> 2) The design GOAL is to have a defined KNOWN box resonance so there is a known roll off below that resonance. Mr. Erath used 70Hz. He put a 15" woofer in a 1.2 cubic ft sealed box and had a FLAT, very accurate and musical response from 18Hz - 125Hz. The Bag End appears to do similar with the 18" woofer. And similarly the only drawback is quantity of output not quality.


I see, it appears I misunderstood your earlier statement. I thought you were referring to a physical resonance of the enclosure _itself_ (like a panel mode), not the resonance of the driver in the enclosure.


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## theJman (Mar 3, 2012)

prerich said:


> BacThey also did a bang up job on the M-6 concentric monitor (my son has a pair finished in Mercedes Benz gloss black)!!!


Have you had the opportunity to hear the M6, and if so what were your impressions? KEF and Tannoy are famous for their concentrics too - I'm intrigued by the concept and potential benefits.


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## prerich (Mar 26, 2008)

Yes, I've heard them at length (my son owns them). They are as good as the speakers you've mentioned! Had some of the most coherent sound I've heard! They are rolled off a little on the top end, but they are exceptional monitors!


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## labman1 (Feb 1, 2013)

Jim ,if you could pick up a couple of these subs fairly new for a $1000 would you do it? How would they do in a 15'x12'x8'9" room. BTW Great review and a job well done!


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## theJman (Mar 3, 2012)

labman1 said:


> Jim ,if you could pick up a couple of these subs fairly new for a $1000 would you do it? How would they do in a 15'x12'x8'9" room. BTW Great review and a job well done!


Your room is a bit less than 1600 ft^3, which is even smaller then mine. A pair of them would perform remarkably well in that space, providing both quality and quantity. If you can get ID-18 Pro's for that price I think it's something you should strongly consider.

If you ultimately decide to go that route you'll owe me an invite to come and hear your system.


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## Owen Bartley (Oct 18, 2006)

That sounds like an amazing deal. If I was in the market for a high end consumer sub (or two!) I would be very VERY tempted to pick up a pair for that price.


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## labman1 (Feb 1, 2013)

The deal is I bought a PSA XS15 6 months ago and was going to get another one with the 5% discount. Should you match your existing sub with another to get the same dynamics and would it not be easier to dial in? I have an 8801 that would apply XT32 to both subs. Now Jim you have me waffling on my idea with your review.:scratch:


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## Owen Bartley (Oct 18, 2006)

It makes sense to match subs generally I think, but then again it also makes sense to upgrade where you can. I'm using a 15 and a 10 at home to help fill in, and haven't had any issues with mismatching. 2 subs of any type should sound better than 1 and if placed in different locations should even out room response. The same sub will sound different in a different location anyway I think. If you were going to co-locate it might make more sense to match, but that's just my guess.


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## theJman (Mar 3, 2012)

labman1 said:


> The deal is I bought a PSA XS15 6 months ago and was going to get another one with the 5% discount. Should you match your existing sub with another to get the same dynamics and would it not be easier to dial in? I have an 8801 that would apply XT32 to both subs. Now Jim you have me waffling on my idea with your review.:scratch:


Whenever possible you should match your existing sub when adding a subsequent unit. Tuning disparate subwoofers is made easier by EQ software, but there are certain things it simply can't overcome. The overal sound quality, dynamics, transient response, etc. are all determined by the engineering and components involved. It's impossible for Audyssey to alter those type of characteristics.

I'm actually very familiar with the XS15 -- I reviewed one when they first came out -- so I know exactly what it sounds like. Frankly, I suspect you'd have significant difficulties getting one of them to blend properly with an ID18. They each have a completely different target audience, and their respective sound signature and abilities differ in a rather significant manner because of it.


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## labman1 (Feb 1, 2013)

Jim my tastes run to Movies and satellite, and Netflix 80% and Music 20% of the time but when I listen to music I like it to be accurate that is why I have Von Schweikert audio 3,5's all around. The Xs15 does a fair job with music and HT. What are you opinions on the XS15? Is there a link to your review? Just want to do the right thing. The subs are going because of a divorce and the wife got the contents. Thanks for your help.

Steve


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## Picture_Shooter (Dec 23, 2007)

labman1 said:


> The deal is I bought a PSA XS15 6 months ago and was going to get another one with the 5% discount. Should you match your existing sub with another to get the same dynamics and would it not be easier to dial in? I have an 8801 that would apply XT32 to both subs. Now Jim you have me waffling on my idea with your review.:scratch:




Hi Labman,

Yes, you bought my XS15  . I will tell you that I had dual XS15s and sold one to you and returned the other one back to PSA. Prior to doing that I tried really hard to blend my Rythmik LV12r (duals) with the XS15 and it didn't blend well at all. I even put the XS15 near field and the sub was just overwhelming in bass notes, so that was why I parted ways with my PSA sub and just kept the Rythmik's.

So I encourage you to get another XS15 and what Jim commented, I totally agree.


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## prerich (Mar 26, 2008)

theJman said:


> Have you had the opportunity to hear the M6, and if so what were your impressions? KEF and Tannoy are famous for their concentrics too - I'm intrigued by the concept and potential benefits.


Ok - I now own my son's M6's and almost made the mistake of selling them because I had too many speakers. The M6's are staying - as a matter of fact - I'm getting a third one to see how they sound in my HT!


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## vdorta (Apr 24, 2008)

I enjoyed the review and it brought back a lot of memories. I am very familiar with Bag End, having listened to its 18" subwoofer a lot many years ago in Trinidad, and then having my dealer friend build me a pair in heavy, custom hardwood enclosures. It's a shame the reviewer only had one of them for review because, as he said, you need at least two of them to have enough headroom. The unorthodox Bag End approach of using the equalized response below driver resonance allows for a seamless and accurate reproduction of bass that's superior to any other subwoofer in my experience. For music, which was and still is my main interest, a pair of them is more than enough for any reasonable situation. Back when I owned them, the only caveat was to use its integrator fed from a preamp subwoofer output, because it wasn't completely transparent to the signal and would add a little veiling to the midrange and highs.


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