I am interested in people's views on this unit's merits / drawbacks relative to say the DEQX / TacT
TAS review of Holm Acoustics DSP1 in this month's edition
- Thread starter Nyal Mellor
- Start date
Nyal, unless you know of a link, I can't lay my hands on this review without paying $50 to join the Golden Ear club, which I'm loathe to do. I did download the RC software manual from Holm's site, and I'll try to read through that this weekend (98 pp!!!).
I read through it. Here is the synopsis. The box first measures the near-field response of the speaker, and then corrects the room. The review was exceptionally positive, praising its fidelity even in a room the author thought was already good sounding. The explanation of what he heard, made absolute sense to me as those are the improvements I have heard just the same. There is a bit of scientific explanation which I found wanting but other than that, it did not include non-sense description of what was heard.
Alas, what you really wanted to hear was a comparative report as Nyal mentions but alas, this is not that. I don't own the box so can't do justice to that comparison either but do own the TacT and did notice a few differences:
1. TacT does not do any speaker correction. This box does. The article rightly points out the challenges in this area though as you have to go through an iterative process of figuring out where to put the mic as otherwise, the signal from all the drivers doesn't blend as it should and author notes that in that case, the box makes things much worse! Solution was to look for dips in response and such which I am not sure is workable for most people wanting to use this box without professional training.
2. Tact, at least the version I have, only optimizes for one listening location (despite the box being the "theater" version). This box as with others like it does multi-point measurement. Now, you can argue for 2-channel music that is not necessary and might degrade performance but it is good to have it.
3. The box does not have multiple settings that you can change on the fly without having a PC hooked up to it. In other words, to change the curve, you need to use the PC software. On Tact, I can store half a dozen settings and switch between them using the remote. I find this super useful as I have different settings for music vs movies.
4. The box uses a USB connection to the PC which is much better than the stupid serial port on my TacT. Not sure if TacT has moved on to USB on their newer boxes but if they have not, this does remove a pain point as no current PC has a serial port and USB converters can be a pain to get working at times.
So it comes down to the merits of speaker correction versus not. Unfortunately the author did not test the system without that correction, nor do we know if that correction is mandatory or not.
We never did succeed in getting a DEQX into our shop so I have no basis for comparison against that unit which also has speaker correction.
Overall, my impression is positive.
Alas, what you really wanted to hear was a comparative report as Nyal mentions but alas, this is not that. I don't own the box so can't do justice to that comparison either but do own the TacT and did notice a few differences:
1. TacT does not do any speaker correction. This box does. The article rightly points out the challenges in this area though as you have to go through an iterative process of figuring out where to put the mic as otherwise, the signal from all the drivers doesn't blend as it should and author notes that in that case, the box makes things much worse! Solution was to look for dips in response and such which I am not sure is workable for most people wanting to use this box without professional training.
2. Tact, at least the version I have, only optimizes for one listening location (despite the box being the "theater" version). This box as with others like it does multi-point measurement. Now, you can argue for 2-channel music that is not necessary and might degrade performance but it is good to have it.
3. The box does not have multiple settings that you can change on the fly without having a PC hooked up to it. In other words, to change the curve, you need to use the PC software. On Tact, I can store half a dozen settings and switch between them using the remote. I find this super useful as I have different settings for music vs movies.
4. The box uses a USB connection to the PC which is much better than the stupid serial port on my TacT. Not sure if TacT has moved on to USB on their newer boxes but if they have not, this does remove a pain point as no current PC has a serial port and USB converters can be a pain to get working at times.
So it comes down to the merits of speaker correction versus not. Unfortunately the author did not test the system without that correction, nor do we know if that correction is mandatory or not.
We never did succeed in getting a DEQX into our shop so I have no basis for comparison against that unit which also has speaker correction.
Overall, my impression is positive.
Hey Amir
What happened to the DEQX unit? I've got a HDP3 with the Jensen balanced output transformers at the moment which I am evaluating for how to integrate it into my work.
DEQX say there will be a review of the HDP-Express in an upcoming issue of TAS, so maybe we'll get a comparison from them at some point in the future. The two units do seem extremely close in functionality and one wonders whether the 10years the DEQX has been on the market would have given them more opportunity to refine the unit. Also it is significantly cheaper than the Holm Acoustics box.
The other units which are interesting in the same digital speaker correction / XO space which people may not have come across are GroundSound www.groundsound.com, MiniDSP www.minidsp.com and Lab Gruppen LM26.
Nyal
What happened to the DEQX unit? I've got a HDP3 with the Jensen balanced output transformers at the moment which I am evaluating for how to integrate it into my work.
DEQX say there will be a review of the HDP-Express in an upcoming issue of TAS, so maybe we'll get a comparison from them at some point in the future. The two units do seem extremely close in functionality and one wonders whether the 10years the DEQX has been on the market would have given them more opportunity to refine the unit. Also it is significantly cheaper than the Holm Acoustics box.
The other units which are interesting in the same digital speaker correction / XO space which people may not have come across are GroundSound www.groundsound.com, MiniDSP www.minidsp.com and Lab Gruppen LM26.
Nyal
No, we didn't get anywhere. I got a PM to follow up which we did but the trail went cold again with emails not being responded to.
I am really puzzled how these companies do business. For us to carry a product like this, we need to know we can count on them communicating with us. And helping us evaluate and compare the product. Parachuting in and out of the forum is not helpful.
I am really puzzled how these companies do business. For us to carry a product like this, we need to know we can count on them communicating with us. And helping us evaluate and compare the product. Parachuting in and out of the forum is not helpful.
I think it must be difficult for them, I'm sure they get a lot of enquiries because they are a small company, sell direct and don't have many distributors.
I find them very response to phone calls, I have called them a few times and always been attended to promptly.
I find them very response to phone calls, I have called them a few times and always been attended to promptly.
That would be fine if I had not gotten a personal PM and assurance that they would follow up. We didn't initiate this last round of communication. They did. And with emails going to an individual person, not sure why follow up is hard.
This area is getting competitive due to cost of DSPs going down so I would think established companies want to cement their position and working with influential people would be a step in that direction.
This area is getting competitive due to cost of DSPs going down so I would think established companies want to cement their position and working with influential people would be a step in that direction.
The review is now on the net:
http://www.avguide.com/review/holm-...l-preamproomspeaker-correction-device-tas-208
In the review REG states:
"There are important features of the DSre1 that distinguish it from previous DSP units. For one thing, it verifies before your very eyes by before-and-after measurements that it did what it was supposed to do. DSP is, in effect, mathematics, and mathematics can be taken on faith—it always works"
The Tact RCS 2.2XP has had the ability to compare before-and-after measurements since it was introduced over three years ago.
Since REG doesn't compare the corrected SQ or the GUI to other DSP units, IMO the review is of little value.
http://www.avguide.com/review/holm-...l-preamproomspeaker-correction-device-tas-208
In the review REG states:
"There are important features of the DSre1 that distinguish it from previous DSP units. For one thing, it verifies before your very eyes by before-and-after measurements that it did what it was supposed to do. DSP is, in effect, mathematics, and mathematics can be taken on faith—it always works"
The Tact RCS 2.2XP has had the ability to compare before-and-after measurements since it was introduced over three years ago.
Since REG doesn't compare the corrected SQ or the GUI to other DSP units, IMO the review is of little value.
Friends,
I expect to have a unit in-house after CES. The fact that REG in TAS likes it is certainly noteworthy, as he has considerable experience over the past 10 years (at least) with this product category. The software can be downloaded for free from their Website if you'd like to look at the GUI. Also, it's a relatively new product, about a year old, with unusual aesthetics and construction which REG did not mention. But they're not afraid to try something new, which is great. Too many products really look like low-volume prototypes; not the Holm.
The Holm distributor in Los Angeles Robert Kelly responds very quickly to inquiries. Nice fellow.
I expect to have a unit in-house after CES. The fact that REG in TAS likes it is certainly noteworthy, as he has considerable experience over the past 10 years (at least) with this product category. The software can be downloaded for free from their Website if you'd like to look at the GUI. Also, it's a relatively new product, about a year old, with unusual aesthetics and construction which REG did not mention. But they're not afraid to try something new, which is great. Too many products really look like low-volume prototypes; not the Holm.
The Holm distributor in Los Angeles Robert Kelly responds very quickly to inquiries. Nice fellow.
Thanks! And of course it's going to be another huge project to get everything sorted out, but it's a great way to learn. Even my limited experimentation with simple EQ software tools in JRMC has been eye-opening and hugely beneficial. As soon as one realizes that pushing the bass way down in the EQ produces much more, and much better real bass, well, live and learn.
Bringing up an old thread, just thought I'd mention something. As most of you know, every year we share a room at RMAF with Usher/JPS Labs. We've had various electronics over the years, but this year I'm proud to announce we'll have Holm Acoustics doing the duty of playing our music. Thomas Holm will be on hand to answer any and all questions. I'm excited and anxious to hear what the DSPre1 and amps can do trying to correct these terrible hotel rooms!
We will also have the advantage of room treatments by Acoustic Fields.
We will also have the advantage of room treatments by Acoustic Fields.
According to: http://www.holmacoustics.com/dspre1_indepth.php#b10
So we have to wait for somebody telling us that Hirez sounds better on this DSpre
So we have to wait for somebody telling us that Hirez sounds better on this DSpre
It is not at all unusual to have low sampling rate in EQ products as the required computational power is proportional to sampling rate. So I suspect that is not a misprint. The JBL Synthesis EQ runs at 96 Khz but I think that is by far the exception than the rule.
Don’t know much about filtering but what I understand is that the number of taps is important for the precision.
If you have 3 FIR filter with 1000 taps each the time you have to calculate 3000 point at a certain sample rate is
44.1 = 0.000023 s
88.2 = 0.000011 s
176.4 = 0.000006 s
Amir’s explanation sounds very plausible to me
If you have 3 FIR filter with 1000 taps each the time you have to calculate 3000 point at a certain sample rate is
44.1 = 0.000023 s
88.2 = 0.000011 s
176.4 = 0.000006 s
Amir’s explanation sounds very plausible to me
Nicholas Bedworth, did you ever evaluate the Holm unit?
Regarding the sample rates: I find it odd that analog is converted to digital at 24/88.2kHz.
The jitter removal section implies that 16/44.1kHz is the native rate and everything else goes through a sample rate converter to 16/44.1kHz, so why convert analog at 24/88.2kHz and then SRC it again to 16/44.1kHz?
The volume control seems to be all digital at yet another sample rate: 24/352.8kHz.
All of which seems to imply a large amount of sample rate conversion regardless of source.
Odd.
Regarding the sample rates: I find it odd that analog is converted to digital at 24/88.2kHz.
The jitter removal section implies that 16/44.1kHz is the native rate and everything else goes through a sample rate converter to 16/44.1kHz, so why convert analog at 24/88.2kHz and then SRC it again to 16/44.1kHz?
The volume control seems to be all digital at yet another sample rate: 24/352.8kHz.
All of which seems to imply a large amount of sample rate conversion regardless of source.
Odd.
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